DD200370B1 - Device on joints of manipulators for weight balance - Google Patents

Description

embodiment

An embodiment is shown in the drawing and will be described in more detail in the following text. In the accompanying drawings show:

Fig. 1 shows the arrangement of the elements for weight balance, Fig. 2, the torque curves.

The device shown in these figures with the weight compensation by springs, rollers and ropes and the associated torque diagram will be described. The static state is characterized by the arrangement according to the invention. On fixed bogie of a robot 1 is the stationary roller 3 in the region of the first joint 2. This is attached to the cable 4 with the same size rotatable roller 9 on the second joint 7, optionally with double wrap and the Seilarretierungen 8 and 10. This loosely rotatable roller 9 of the second articulation is also connected to the same one of the third articulation, and so forth. The counterbalance spring 5 is fixed at one end to the arm and at the other end to the first pin 11 of the adjusting device. The spring for the flanking device 6 is attached to the second pin of the adjusting device 12 and depending on the position of the arm, it is on the third pin of the adjusting device 13 or not. The function of the device is as follows. A spring force F1 generated with the lever arm r1 a left-handed torque, which is greatest in the horizontal position of the arm and decreases to the upper and lower vertical position to zero. The resulting torque 16

M ₁ = F ₁ · r, · sin et, counteracts the torque 15, which is caused by the gravitational force G with the lever arm I as

M, = G · I · sin α

In the vertical position of the arm, the spring force F ₂ causes a right-handed torque in the angular range

0 ° <α <90 °

M ₂ = F ₂ .r ₂ .cos α

is described

 In the angle range

90 ° <a <180 °

acts the extended lever arm r ₃ with the spring force F ₂ and there is also a right-handed torque 17 M ₂ = F ₂ - T ₃ COs (α- 180 °).

In Fig. 2, the torque characteristics are shown qualitatively. In the considerations, the force increases are neglected by the elongation of the springs. The reaction torques that occur on the loose roll are transferred via the ropes to the fixed roll and cause additional buoyancy of the first joint when only the following arms are pivoted. The points of attack of the springs are adjustable on the rollers in the radial direction in order to realize the flanking of the tooth pairings in the gears with different forces or torques. The behavior transforms to the other joints and realizes the flank system according to the same principle.

Contemplated documents: EP 024 433- (B 25 J, 17/00)

Claims (2)

Invention claim: 1. Device to joints of manipulators for balancing the weight by means of springs on double friction disks or pairs locked ropes, straps and the like. On castors or modified from parallelograms a stationary basic position is transmitted to a subsequent joint, characterized in that spring fasteners on the one hand movable arm and on the other hand over up to three offset by 90 ° adjusting means (11,12,13) are provided, both on a first stationary roller (3), the non-rotatable on the frame (1) in the first joint (2) of the arm is attached, as well as to the subsequent rollers (9) in the joints (7,17) of the forearm and hand, so that the springs (5, 6) are tensioned directly or via rollers or lever arms. 2. Apparatus according to claim 1, characterized in that the pin (11) formed point of an adjusting device (11) for fixing a spring (5) over the axis of rotation, while a second spring (6) offset by 90 ° to has two attack points (12/13) as adjusting devices. For this 2 pages drawings Field of application of the invention The invention relates to a device on articulated joints of manipulators, in which the weight is balanced by low-weight elements via deflected forces. Characteristic of the known technical solutions Many solutions are known for balancing the weights of manipulator arms and eliminating or alleviating self-adjusting or constructional clearance of the joints, and particularly gear transmissions. Likewise, the corresponding arrangement is made for the reduction of dead masses z. As the drive part, such as engine and transmission parts as a counterweight of the arm, with the joint in between. A disadvantage is occasionally additional space when manipulating and almost double rotating mass. It has already been proposed in the application WP B 25 J / 225 289, with clamping bands on discs on the joints to move the heavier drive part to the more stable lower arm parts. Disadvantages are a higher design effort with just such assembly and that a removal of the game, especially in simple gearboxes, is not reached automatically. Due to the continuously acting clamping force, a higher wear of the bearing joints is to be expected or a more stable, ie heavier construction is required. It was also proposed in the application WP B 25 J / 225 156 to apply substantially only for the first joint a cam with bolts under spring pressure. Additional disadvantages are the above-mentioned and the possible achievement of the self-locking of this transmission of forces. Object of the invention It is the object of the invention, in particular, to use economical and easy-to-manufacture mechanical elements in the joints of robots for fine-mechanical manufacturing requirements and to counteract their inevitably faster-adjusting wear phenomena. No additional dead masses are required for taring the individual arms of the robot, which do not fully utilize the torques of the motors for the accelerations. Explanation of the essence of the invention - The technical problem which is solved by the invention The invention is based on the object, the technical means with their advantageous properties, such. B. simple worm gear with stepper motors as drive to joints of articulated robots and the non-positive and low-mass force of springs under elimination of adverse effects for a faster in the end more accurate and low-wear operation of the same use. Features of the invention According to the invention the object is achieved in that arrangements and dimensions of known per se elements are combined to form a combined system at the joints of manipulators. Thus, a fixed role and for each articulated loose rollers and connected to these pairs locked ropes with springs of certain characteristics for the compensation of the respective arm masses by adjusting different tension. A feature of the invention is the transmission of the absolute angular position from one joint to the other, achieved by pairs of equal-sized rollers. The rolling diameter of two connected by a common rope roles are thus the same size. Another feature of the invention is achieved by springs of certain characteristics, which are adjusted by means of the adjusting device so that the load torque of the joint gear acts independently of gravity by the retention z. B. unilateral flank system is guaranteed in the gear joint gear of the sum of the forces. It is in particular with the fixed role z. B. achieved on the bogie of a robot, that the spring attack points on the rollers regardless of the arm positions of all articulated arms always take the same absolute angular positions to the direction of gravity. The points of attack of the springs on the rollers must be adjustable for the purpose of locking and both attack points of the spring system relative to the roller relative to its axis of rotation to be arranged offset by 90 °. It is advantageous if the approach of the spring force on the effective lever arm by its adjustment at different positions of the articulated arms is effective as a compensation torque.