Development Of Sealed Three Piece Master Slave Manipulator,
This document was uploaded by user and they confirmed that they have the permission to share it. If you are author or own the copyright of this book, please report to us by using this DMCA report form. Report DMCA
Overview
Download & View Development Of Sealed Three Piece Master Slave Manipulator, as PDF for free.
More details
- Words: 2,779
- Pages: 5
DEVELOPMENT OF SEALED THREE PIECE MASTER SLAVE MANIPULATOR B. Sony, Vivek Mahadev1, K. Jayarajan, Manjit Singh Division of Remote Handling and Robotics Bhabha Atomic Research Centre, Trombay, Mumbai-400 085 1 Seismology Division email: [email protected] Abstract: In nuclear industry, radioactive materials are handled in heavily shielded rooms, called hotcells. As human access is restricted, remote handling tools are necessary to perform any handling operations in these cells. Master Slave Manipulators (MSMs) are the commonly used remote handling tools in hotcells. From the control station, operator controls the master arm of the manipulator by moving its hand grip. The manipulator transmits the motion and force applied on the hand grip through a series of mechanical linkages and reproduces them at the slave gripper inside the hotcell. Sealed Type Three-Piece Manipulator (TPM) is an advanced version of MSM. Its unique feature is modularity; its slave arm can be remotely attached or detached in the hotcell. It is also sealed to isolate the hotcell from the outside. Keywords: remote handling, radiation, hotcell, teleoperation, manipulator. 1.
INTRODUCTION
Remote handling is the operation of performing manual tasks, in absence of human operator at the work site (Jean Vertut). It enables personnel to maintain a safe working distance from hazardous work environment. Remoteness of task and hard-to-access task locations also demands the use of remote handling tools to perform the task. In areas like tele-surgery, remote handling tools are also used to enhance human hand movements. Although, automated systems can be used for repetitive operations in a well structured environment, human assistance is necessary for any unplanned remote handling in an unstructured environment. In the nuclear industry, remote handling tools play a dominant role in handling radioactive materials. Areas in the nuclear industry where remote handling tools are used include fuel fabrication, fuel reprocessing, waste management, post irradiation examination and radioisotope production (Jayarajan 2006). Nuclear industry comes across various radioactive materials emitting radiation of various energies, penetrating power and hazards. Various techniques are employed in their storage and handling. High active radioisotopes are handled in heavily shielded rooms, called hotcells. Hotcell walls and ceiling are made of 1 m to 2 m thick concrete to absorb the nuclear radiation. Hotcells may be sealed or unsealed, depending on the type of radioactivity handled in the cell. They are usually maintained at negative pressure with reference to the operating area to prevent any leakage of contaminated air. Hotcells are generally viewed through shielded glass windows. As personnel access is restricted, all handling operations in the hotcells are performed using remote handling tools such as in-cell cranes, power manipulators and master slave manipulators (MSMs). While in-cell crane and power manipulators are used for handling heavy jobs, where precision in handling is not important, master slave manipulators are used for precision handling.
Design a remote handling tool for nuclear applications is a challenging task. The equipment should have high reliability, should have some mechanism for withdrawal in the event of a failure at site, and should be made up of radiation resistant materials and components. 2.
MASTER SLAVE MANIPULATORS
MSM is the most widely used general-purpose remote handling tool in nuclear industry. In master slave manipulation, human being is within the process, and his abilities are extended to the remote place. An MSM consists of two arms, a master arm placed at control station (outside the hotcell), and a slave arm placed inside the cell to perform a remote task. Figure 1 shows the mounting arrangement of a mechanical MSM on the hotcell wall.
Fig. 1. MSM mounting Both the master and the slave arms have six independent motions and end effectors (handgrip and gripper respectively) which can open and close. To perform any task, the operator holds and manipulates the handgrip on the master arm. The motions of the handgrip
are reproduced by the gripper on the slave arm inside the hotcell. In cells, where mechanical manipulators are used, a viewing window is positioned between the two arms, through which the operator can observe the work area. In most of the cases, the master arm and the slave arm are made geometrically similar. MSMs are usually used in pairs, and operator manipulates the master arms using both his hands. 2.1 MSM Classification MSMs are broadly classified as mechanical manipulators and servo manipulators, based on the power source available for the slave arm. In mechanical manipulator, the power source is human operator and the force and motion applied by him is transmitted to the slave arm through mechanical linkages. Servomanipulators have their own mechanical power sources for their slave arms, such as electric motors or hydraulic cylinders. Signal transmission from the master to the slave is through electric cables or wireless. Based on the type of joints, mechanical MSMs are classified into two categories: articulated and telescopic. In an articulated MSM, all joints are of revolute (articulated) type. It is suitable for small work area, and light load applications. Telescopic manipulators have at least one linear (telescopic) joint. They can transmit higher operating forces and are suitable for large size cells. All mechanical manipulators, either articulated or telescopic type, have an inherent bilateral control which allows the force acting on the slave side to be transmitted to the master side. Ability to feel and control the applied force helps the operator to perform the task accurately. Further, MSMs are classified based on their load carrying capacities. A light duty MSM can handle upto 10 kg load. The heavy duty MSM has a payload capacity of 20 kg, while the Rugged Duty MSM can operate upto 45 kg load. Division of Remote Handling and Robotics (DRHR) of Bhabha Atomic Research Center, Mumbai has developed several manipulators with varying payloads and ranges. Three-piece manipulator is the latest development in this area. 3.
THREE PIECE MANIPULATOR
The Three Piece MSM is a telescopic type heavy duty mechanical manipulator (Jayarajan & Manjit Singh 2006). The unique feature of TPM is its modular construction. It has three distinct and easily separable parts: the slave arm, the through tube, and the master arm. It is essential that the entire manipulator be light in weight and low on inertia to reduce operating effort and strong enough to withstand high forces in loaded condition. Hence the components used in the master and the slave arms are manufactured using materials of high strength to weight ratio. The manipulator must also be reliable, smooth to operate, and should have low friction and lost motion. A great care is taken to ensure that adequate precision and accuracy levels are maintained
during the design stage, and high quality standards are followed during the fabrication of TPM. 3.1 Manipulator Design The master arm of TPM is an assembly of two coaxial circular tubes such that the inner (boom) tube can telescopically slide and rotate within the outer tube as shown in figure 2. The lower end of boom tube supports a mechanical wrist joint which generates motions similar to a human wrist. The wrist joint supports the handgrip which is analogous to human fingers. The shoulder joint allows the arm to execute a to-and-fro swinging motion in a vertical plane.
Fig. 2. TPM construction The slave arm has an assembly of three coaxial tubes as shown in figure 2. The largest diameter outer tube is suspended from the shoulder joint and supports a telescopically sliding intermediate tube. The telescopic motion of intermediate tube is controlled by an electrical actuator. The smallest diameter boom tube can slide and rotate within the intermediate tube. It reproduces the motion of master arm boom tube. A wrist joint identical to master arm wrist is attached on the slave arm and carries a twin finger gripper for grasping objects. The through tube is made up of a mild steel outer body of circular cross section. It contains seven rotary shafts supported on bearings. Each shaft transmits one manipulator motion from the master arm to the slave arm. The through tube is fitted with lead blocks to provide radiation shielding as shown. 3.2 Mechanical Joints TPM has six manual motions available on each arm and a squeeze (open and close) motion for the end effector operation. The motions are illustrated in Figure 3. X motion is the back and forth swing of the manipulator about the through tube axis. Y is the swivel motion of the arms about the shoulder joint. The linear telescopic travel of boom tubes is termed as Z motion. X, Y and Z motions are essential to reach any coordinate in three dimensional space. Azimuth (Az) motion is the rotational capability of the boom tube. Motions Wr and We are the two rotational wrist motions. These six
motions can collectively position and orient the gripper in any arbitrary configuration.
Fig. 3. TPM manual motions 3.3 Electrical Joints The X, Y and Z motions can also be electrically operated using electrical actuators provided on the master arm. During electrical operation the master arm is stationary and the slave arm is in motion as shown in figure 4. Due to Z electrical (Ze) motion occurring on the intermediate tube, the slave arm has an extended reach. Motions ‘Xe’ and ‘Ye’ enable the operator to move the slave arm along these directions beyond the operating range of the master arm. The electrical indexing motions enable the slave arm to operate in more work volume than that of the human arm. It also enables the operator to stand in a comfortable posture for operation and viewing.
Fig. 4. TPM electrical motions 3.4 Motion transmission Power transmission between the master arm and the slave arm is the most challenging task in mechanical manipulator design. It is designed such that the slave gripper reproduces the motion applied on the master, keeping the same magnitude and direction. In addition, the applied force/ torque on master are to be reflected on the slave and vice versa. For faster and accurate gripper positioning, the motion transmission should be rigid, positive and backlash-free. Friction, gravity load and inertia of manipulator are to be minimised to reduce operator’s fatigue.
Fig. 5. Transmission of azimuth motion Unlike other MSMs, TPM uses parallel rotating shafts for power transmission along the through-tube. This feature is effectively used in indigenous TPM to provide sealing and shielding across the cell wall. With the exception of X and Y, all motions are transmitted from the master arm joints to the respective slave arm joints through a combination of spur and bevel gears, wire rope and pulleys, and, roller chain and sprockets. In figure 5, transmission of azimuth rotation from master arm to the through tube is shown in detail. At the upper end of the boom tube, the azimuth assembly [1] is mounted. As shown above, it consists of a bevel gear attached to the boom tube and supported by a ball bearing within a housing. The gear is in mesh with a pinion integral with a wire rope drum. Any rotation of boom tube is transferred to the drum with this arrangement. A pair of wire ropes carries the drum rotation motion over a series of pulleys to another wire rope drum [3] as shown in figure 5. Using bevel gearing the drum rotation is converted to shaft [4] rotation and transmitted to slave side where a similar arrangement of gears and wire ropes generate the azimuth rotation on slave arm boom tube. Similar wire rope arrangement is used to transmit each motion, except X and Y. The carriage [2] always moves in a direction opposite to the boom tube travel and by half the distance, thereby providing compensation for wire rope length when Z motion is operated. 3.5 Special features Apart from its three piece modular design, TPM has some special features incorporated in its design to enhance the operability of the equipment. 3.5.1 Balancing The gravity loads of the master and the slave arms would act on the operator if they are not compensated.
Lead counterweights are rigidly mounted on the master arm to balance the weights of both master and slave arms. Manual and electrical motions along Z direction displace the centre of gravities on both arms creating dynamic arm loads. TPM has movable counterweights installed on master arm to balance dynamic loads.
3.5.6 Shielding Shielding within the through-tube is provided as an optional feature in MSMs. It reduces the amount of radiation penetrating from the hotcell at the through-tube level. Shielding is better achieved in manipulators of three-piece construction.
3.5.2 Sealing 3.6 Installation Leakage of air from hotcell to outside through the mounting port should be minimized. The through tube of TPM is fitted with a modular sealing unit located near the master side. Seven shaft segments, each fitted with two rotary oil seals and mounted on ball bearings, pass through the unit. The unit, when filled with oil, prevents air leakage from the through tube. Figure 6 shows how sealing is implemented in the through tube.
Fig. 6. Sealing arrangement 3.5.3 Detachable wrist The wrist joint of slave and master arms can be detached from the boom tube. The wrist joint transmits motion to the end effector using three gear trains. Wrist removal is accomplished by meshing and unmeshing of gears on individual trains at the detachment junction. 3.5.4 Motion Locks Motion locks are used to lock the manipulator joints rigidly in any position. It also facilitates installation and removal of the manipulator. 3.5.5 Remotely Replaceable Jaws The only parts of manipulator that come into contact with the objects in hotcell are the jaw friction-pads of the slave tong. Friction pads need periodic replacement. By remote replacement, the jaws can quickly adapt to gripping surfaces of different sizes and shapes.
The hotcell walls have circular openings (ports) of 10” diameter embedded with stainless steel linings. The ports are located at a height of 3 m from the floor level and are used to mount the master slave manipulators. The principal advantage of TPM over other mechanical manipulators is its simplified installation procedure in the hotcell. As shown in figure 3, the slave arm and the master arm can be easily detached from the through tube. This feature greatly simplifies the installation procedures.
Fig. 7. Installation procedure The entire manipulator can be installed in parts. Initially the through tube is inserted into the circular port from the master side and fastened rigidly in place. The slave arm is taken into the cell and assembled with the through tube using a crane as shown in figure 3. The master arm can be similarly assembled with the through tube from the operating area using a hoist or a crane (not shown in figure). If some breakdown occurs on the slave arm, it can be quickly disengaged and detached from the through tube by operating a simple locking mechanism from the master side and lowered down using the in-cell crane. The through tube and master arm remain in place. A working slave arm, if available, can be installed to minimize downtime.
3.7 Technical specifications Motion name X Motion Y Motion Z Motion Azimuth rotation Wrist rotation Wrist elevation Tong opening X electrical motion Y electrical motion Z electrical motion
Range +60°, -60° +25°, -20° 970 mm +170°, -170° +270°, -270° +116°, -24° 80 mm +30°, -30° +70°, -20° 910 mm
Table 1. Range of motion The manual and electrical motions of TPM have a definite range. These values are listed in table 1. Each motion is designed to safely operate at a particular load rating. The load values are mentioned in table 2. Description X motion Y motion Z motion Azimuth rotation Wrist rotation Wrist elevation Tong
Rated load 20 kg 20 kg 20 kg 300 kg-cm 100 kg-cm 300 kg-cm 20 kg
Table 2. Load capacity 4.
CONCLUSION
Three-piece manipulator is an advanced version of mechanical master slave manipulator. Unlike other manipulators, TPM is modular in construction. It can be easily separated into three parts: the master arm, the slave arm and the trough-tube. Its slave arm can be remotely attached and detached from the hotcell, without withdrawing of the manipulator from the cell and without the personnel entry into the cell. This feature makes the installation and maintenance easier. Another unique feature of TPM is its shielding, which isolates hotcell atmosphere from the operating area. Sealing integrity is maintained, even when the slave arm or the master arm is detached. 5.
REFERENCES
Jean Vertut & Phillipee Coiffet; Robot technologies, Volume 3a – IBH Jayarajan K. & Manjit Singh (2006), Master Slave Manipulators: Technology and Recent Developments, BARC Newsletter Vol. No. 269, June 2006
Jayarajan K. (2006), Remote Handling Technology in Nuclear Industry, Proc. of the BARC Golden Jubilee Workshop on “Emerging Technologies of the Future”, October 27, 2006
INTRODUCTION
Remote handling is the operation of performing manual tasks, in absence of human operator at the work site (Jean Vertut). It enables personnel to maintain a safe working distance from hazardous work environment. Remoteness of task and hard-to-access task locations also demands the use of remote handling tools to perform the task. In areas like tele-surgery, remote handling tools are also used to enhance human hand movements. Although, automated systems can be used for repetitive operations in a well structured environment, human assistance is necessary for any unplanned remote handling in an unstructured environment. In the nuclear industry, remote handling tools play a dominant role in handling radioactive materials. Areas in the nuclear industry where remote handling tools are used include fuel fabrication, fuel reprocessing, waste management, post irradiation examination and radioisotope production (Jayarajan 2006). Nuclear industry comes across various radioactive materials emitting radiation of various energies, penetrating power and hazards. Various techniques are employed in their storage and handling. High active radioisotopes are handled in heavily shielded rooms, called hotcells. Hotcell walls and ceiling are made of 1 m to 2 m thick concrete to absorb the nuclear radiation. Hotcells may be sealed or unsealed, depending on the type of radioactivity handled in the cell. They are usually maintained at negative pressure with reference to the operating area to prevent any leakage of contaminated air. Hotcells are generally viewed through shielded glass windows. As personnel access is restricted, all handling operations in the hotcells are performed using remote handling tools such as in-cell cranes, power manipulators and master slave manipulators (MSMs). While in-cell crane and power manipulators are used for handling heavy jobs, where precision in handling is not important, master slave manipulators are used for precision handling.
Design a remote handling tool for nuclear applications is a challenging task. The equipment should have high reliability, should have some mechanism for withdrawal in the event of a failure at site, and should be made up of radiation resistant materials and components. 2.
MASTER SLAVE MANIPULATORS
MSM is the most widely used general-purpose remote handling tool in nuclear industry. In master slave manipulation, human being is within the process, and his abilities are extended to the remote place. An MSM consists of two arms, a master arm placed at control station (outside the hotcell), and a slave arm placed inside the cell to perform a remote task. Figure 1 shows the mounting arrangement of a mechanical MSM on the hotcell wall.
Fig. 1. MSM mounting Both the master and the slave arms have six independent motions and end effectors (handgrip and gripper respectively) which can open and close. To perform any task, the operator holds and manipulates the handgrip on the master arm. The motions of the handgrip
are reproduced by the gripper on the slave arm inside the hotcell. In cells, where mechanical manipulators are used, a viewing window is positioned between the two arms, through which the operator can observe the work area. In most of the cases, the master arm and the slave arm are made geometrically similar. MSMs are usually used in pairs, and operator manipulates the master arms using both his hands. 2.1 MSM Classification MSMs are broadly classified as mechanical manipulators and servo manipulators, based on the power source available for the slave arm. In mechanical manipulator, the power source is human operator and the force and motion applied by him is transmitted to the slave arm through mechanical linkages. Servomanipulators have their own mechanical power sources for their slave arms, such as electric motors or hydraulic cylinders. Signal transmission from the master to the slave is through electric cables or wireless. Based on the type of joints, mechanical MSMs are classified into two categories: articulated and telescopic. In an articulated MSM, all joints are of revolute (articulated) type. It is suitable for small work area, and light load applications. Telescopic manipulators have at least one linear (telescopic) joint. They can transmit higher operating forces and are suitable for large size cells. All mechanical manipulators, either articulated or telescopic type, have an inherent bilateral control which allows the force acting on the slave side to be transmitted to the master side. Ability to feel and control the applied force helps the operator to perform the task accurately. Further, MSMs are classified based on their load carrying capacities. A light duty MSM can handle upto 10 kg load. The heavy duty MSM has a payload capacity of 20 kg, while the Rugged Duty MSM can operate upto 45 kg load. Division of Remote Handling and Robotics (DRHR) of Bhabha Atomic Research Center, Mumbai has developed several manipulators with varying payloads and ranges. Three-piece manipulator is the latest development in this area. 3.
THREE PIECE MANIPULATOR
The Three Piece MSM is a telescopic type heavy duty mechanical manipulator (Jayarajan & Manjit Singh 2006). The unique feature of TPM is its modular construction. It has three distinct and easily separable parts: the slave arm, the through tube, and the master arm. It is essential that the entire manipulator be light in weight and low on inertia to reduce operating effort and strong enough to withstand high forces in loaded condition. Hence the components used in the master and the slave arms are manufactured using materials of high strength to weight ratio. The manipulator must also be reliable, smooth to operate, and should have low friction and lost motion. A great care is taken to ensure that adequate precision and accuracy levels are maintained
during the design stage, and high quality standards are followed during the fabrication of TPM. 3.1 Manipulator Design The master arm of TPM is an assembly of two coaxial circular tubes such that the inner (boom) tube can telescopically slide and rotate within the outer tube as shown in figure 2. The lower end of boom tube supports a mechanical wrist joint which generates motions similar to a human wrist. The wrist joint supports the handgrip which is analogous to human fingers. The shoulder joint allows the arm to execute a to-and-fro swinging motion in a vertical plane.
Fig. 2. TPM construction The slave arm has an assembly of three coaxial tubes as shown in figure 2. The largest diameter outer tube is suspended from the shoulder joint and supports a telescopically sliding intermediate tube. The telescopic motion of intermediate tube is controlled by an electrical actuator. The smallest diameter boom tube can slide and rotate within the intermediate tube. It reproduces the motion of master arm boom tube. A wrist joint identical to master arm wrist is attached on the slave arm and carries a twin finger gripper for grasping objects. The through tube is made up of a mild steel outer body of circular cross section. It contains seven rotary shafts supported on bearings. Each shaft transmits one manipulator motion from the master arm to the slave arm. The through tube is fitted with lead blocks to provide radiation shielding as shown. 3.2 Mechanical Joints TPM has six manual motions available on each arm and a squeeze (open and close) motion for the end effector operation. The motions are illustrated in Figure 3. X motion is the back and forth swing of the manipulator about the through tube axis. Y is the swivel motion of the arms about the shoulder joint. The linear telescopic travel of boom tubes is termed as Z motion. X, Y and Z motions are essential to reach any coordinate in three dimensional space. Azimuth (Az) motion is the rotational capability of the boom tube. Motions Wr and We are the two rotational wrist motions. These six
motions can collectively position and orient the gripper in any arbitrary configuration.
Fig. 3. TPM manual motions 3.3 Electrical Joints The X, Y and Z motions can also be electrically operated using electrical actuators provided on the master arm. During electrical operation the master arm is stationary and the slave arm is in motion as shown in figure 4. Due to Z electrical (Ze) motion occurring on the intermediate tube, the slave arm has an extended reach. Motions ‘Xe’ and ‘Ye’ enable the operator to move the slave arm along these directions beyond the operating range of the master arm. The electrical indexing motions enable the slave arm to operate in more work volume than that of the human arm. It also enables the operator to stand in a comfortable posture for operation and viewing.
Fig. 4. TPM electrical motions 3.4 Motion transmission Power transmission between the master arm and the slave arm is the most challenging task in mechanical manipulator design. It is designed such that the slave gripper reproduces the motion applied on the master, keeping the same magnitude and direction. In addition, the applied force/ torque on master are to be reflected on the slave and vice versa. For faster and accurate gripper positioning, the motion transmission should be rigid, positive and backlash-free. Friction, gravity load and inertia of manipulator are to be minimised to reduce operator’s fatigue.
Fig. 5. Transmission of azimuth motion Unlike other MSMs, TPM uses parallel rotating shafts for power transmission along the through-tube. This feature is effectively used in indigenous TPM to provide sealing and shielding across the cell wall. With the exception of X and Y, all motions are transmitted from the master arm joints to the respective slave arm joints through a combination of spur and bevel gears, wire rope and pulleys, and, roller chain and sprockets. In figure 5, transmission of azimuth rotation from master arm to the through tube is shown in detail. At the upper end of the boom tube, the azimuth assembly [1] is mounted. As shown above, it consists of a bevel gear attached to the boom tube and supported by a ball bearing within a housing. The gear is in mesh with a pinion integral with a wire rope drum. Any rotation of boom tube is transferred to the drum with this arrangement. A pair of wire ropes carries the drum rotation motion over a series of pulleys to another wire rope drum [3] as shown in figure 5. Using bevel gearing the drum rotation is converted to shaft [4] rotation and transmitted to slave side where a similar arrangement of gears and wire ropes generate the azimuth rotation on slave arm boom tube. Similar wire rope arrangement is used to transmit each motion, except X and Y. The carriage [2] always moves in a direction opposite to the boom tube travel and by half the distance, thereby providing compensation for wire rope length when Z motion is operated. 3.5 Special features Apart from its three piece modular design, TPM has some special features incorporated in its design to enhance the operability of the equipment. 3.5.1 Balancing The gravity loads of the master and the slave arms would act on the operator if they are not compensated.
Lead counterweights are rigidly mounted on the master arm to balance the weights of both master and slave arms. Manual and electrical motions along Z direction displace the centre of gravities on both arms creating dynamic arm loads. TPM has movable counterweights installed on master arm to balance dynamic loads.
3.5.6 Shielding Shielding within the through-tube is provided as an optional feature in MSMs. It reduces the amount of radiation penetrating from the hotcell at the through-tube level. Shielding is better achieved in manipulators of three-piece construction.
3.5.2 Sealing 3.6 Installation Leakage of air from hotcell to outside through the mounting port should be minimized. The through tube of TPM is fitted with a modular sealing unit located near the master side. Seven shaft segments, each fitted with two rotary oil seals and mounted on ball bearings, pass through the unit. The unit, when filled with oil, prevents air leakage from the through tube. Figure 6 shows how sealing is implemented in the through tube.
Fig. 6. Sealing arrangement 3.5.3 Detachable wrist The wrist joint of slave and master arms can be detached from the boom tube. The wrist joint transmits motion to the end effector using three gear trains. Wrist removal is accomplished by meshing and unmeshing of gears on individual trains at the detachment junction. 3.5.4 Motion Locks Motion locks are used to lock the manipulator joints rigidly in any position. It also facilitates installation and removal of the manipulator. 3.5.5 Remotely Replaceable Jaws The only parts of manipulator that come into contact with the objects in hotcell are the jaw friction-pads of the slave tong. Friction pads need periodic replacement. By remote replacement, the jaws can quickly adapt to gripping surfaces of different sizes and shapes.
The hotcell walls have circular openings (ports) of 10” diameter embedded with stainless steel linings. The ports are located at a height of 3 m from the floor level and are used to mount the master slave manipulators. The principal advantage of TPM over other mechanical manipulators is its simplified installation procedure in the hotcell. As shown in figure 3, the slave arm and the master arm can be easily detached from the through tube. This feature greatly simplifies the installation procedures.
Fig. 7. Installation procedure The entire manipulator can be installed in parts. Initially the through tube is inserted into the circular port from the master side and fastened rigidly in place. The slave arm is taken into the cell and assembled with the through tube using a crane as shown in figure 3. The master arm can be similarly assembled with the through tube from the operating area using a hoist or a crane (not shown in figure). If some breakdown occurs on the slave arm, it can be quickly disengaged and detached from the through tube by operating a simple locking mechanism from the master side and lowered down using the in-cell crane. The through tube and master arm remain in place. A working slave arm, if available, can be installed to minimize downtime.
3.7 Technical specifications Motion name X Motion Y Motion Z Motion Azimuth rotation Wrist rotation Wrist elevation Tong opening X electrical motion Y electrical motion Z electrical motion
Range +60°, -60° +25°, -20° 970 mm +170°, -170° +270°, -270° +116°, -24° 80 mm +30°, -30° +70°, -20° 910 mm
Table 1. Range of motion The manual and electrical motions of TPM have a definite range. These values are listed in table 1. Each motion is designed to safely operate at a particular load rating. The load values are mentioned in table 2. Description X motion Y motion Z motion Azimuth rotation Wrist rotation Wrist elevation Tong
Rated load 20 kg 20 kg 20 kg 300 kg-cm 100 kg-cm 300 kg-cm 20 kg
Table 2. Load capacity 4.
CONCLUSION
Three-piece manipulator is an advanced version of mechanical master slave manipulator. Unlike other manipulators, TPM is modular in construction. It can be easily separated into three parts: the master arm, the slave arm and the trough-tube. Its slave arm can be remotely attached and detached from the hotcell, without withdrawing of the manipulator from the cell and without the personnel entry into the cell. This feature makes the installation and maintenance easier. Another unique feature of TPM is its shielding, which isolates hotcell atmosphere from the operating area. Sealing integrity is maintained, even when the slave arm or the master arm is detached. 5.
REFERENCES
Jean Vertut & Phillipee Coiffet; Robot technologies, Volume 3a – IBH Jayarajan K. & Manjit Singh (2006), Master Slave Manipulators: Technology and Recent Developments, BARC Newsletter Vol. No. 269, June 2006
Jayarajan K. (2006), Remote Handling Technology in Nuclear Industry, Proc. of the BARC Golden Jubilee Workshop on “Emerging Technologies of the Future”, October 27, 2006
Related Documents
Master Manipulator
June 2020 88
Master Manipulator
December 2019 33
Three Stages Of Human Development
October 2019 32
Sealed
June 2020 18
Friedrich Nietzsche Master And Slave Morality
May 2020 10More Documents from "martin"
