Patent GB-1108873-A (GB)
Title: Remote-control manipulator
Inventor: AINSWORTH ALAN
IPC: B25J9/10
Filed: 1965-06-22
Abstract: 1,108,873. Master slave manipulators. UNITED KINGDOM ATOMIC ENERGY AUTHORITY. 9 June, 1966 [22 June, 1965], No. 26444/65. Heading B4Q. [Also in Division G1] In a remote control manipulator whose slave arm is caused to follow movements of its master arm by comparing the electrical characteristics of transducers associated with the movements of the two arms respectively and causing a fluid motor associated with the slave arm to be operated to bring it into correspondence with the master arm, means are also provided for moving the slave arm at least in one direction without moving the master arm. In the embodiment, the master and slave arms, each having 6 degrees of freedom, comprise upper arms 11, 12, Figs. 1A, 1B, pivoted at 7 and 8 respectively to brackets 5, 6 the former being attached to a collar 19 rotatable about a beam 2 to which the bracket 6 is attached. The beam 2 is itself rotatable in a sealed aperture in a cabinet wall 1. Wrist units 15, 16, carried at the lower ends of lower arms 13, 14, each rotatable and slidable within the upper arms, carry a hand grip 17 and a work gripper 18 respectively. These grippers 17, 18 are mounted for flexure and twist with respect to the wrist units. Flexure and twist of the gripper of the slave arm is effected by operation of two hydraulic rams 30, whose ram rods 31 are attached to chains 28, extending round sprockets 27 mounted on an axle 22, on which bevel gears 25 are also mounted. These gears 25 mesh with a further bevel gear 26, rigid with the gripper, so that, depending on whether the gears 25 rotate in the same or opposite directions, the grippers are flexed or twisted. These movements are detected by two variable rotary resistors 69, geared to the bevel gear driver 25a. In the master arm, flexure or twist of the grip 17 is detected by variable rotary resistors 70. In a similar manner, rotation and telescopic movement of the lower slave arm relative to its upper arm are effected respectively by rams 39 and 42 and detected by rotary resistors 72a and 76. Rotary resistors 75, 76a respectively detect similar movement of the master arm. Fore and aft and lateral movement of the slave arm relating to the wall 1 is effected similarly by rams 45, (52), Fig. 3 (not shown), respectively and detected by linear variable resistors 83, 92, Fig. 1A. Equivalent movement of the master arm is detected by linear resistors 87, 95. Movement of the jaws 116 of the work gripper 18 is effected by a ram 117, a linear resistor 120 detecting movement of the jaws, which are spring-loaded, into their open position. A similar variable resistor 123 in the master arm senses the position of its two fingers. In operation, the potentials from each pair of related transducers, e.g. the linear resistors 83, 87, Fig. 4 (not shown), are delivered to an amplifier (101) and thence to the torque coils of a servo valve (102) which energizes, e.g. the ram 47 in accordance with the difference between the signals. For the operation, of the jaws 116, a variable valve is connected, into the hydraulic circuit which is adjustable between three settings, to vary the power applied to the grippers to a range appropriates to the weight of the equipment to be handled. Movement of the slave arm without corresponding movement of the master arm is obtained, e.g. for fore and aft movement, by actuating a switch 104, previously actuated by a switch 105 on the hand gripper 17, to operate a valve (103) which displaces the cylinder 46 on the slave arm relative to the rod 48, to produce the required movement of the slave arm. This movement does not effect the relative positions of the linear resistor 83 and the ram 47, so that this change of position does not effect the signal transmitted by the potentiometer. In a similar way lateral movement of the slave arm relative to the master arm is effected by energizing a ram 63 by actuation of a switch on the master arm, to move the linkage 58, 60 thereby rotating the beam. This rotation does not again alter the setting on the variable resistor 92. Finally telescopic movement of the slave lower arm with respect to its upper arm can be made by adjusting a resistance 115, connected in series with the transducer 76a in the master arm. This effectively unbalances the master and slave arm circuits causing the slave arm to be moved to correct the unbalance.