Question

How should the motor of this robotic arm be chosen? This robotic arm has a total of four motors, one on the arm, one on the wrist, one on the claw and one on the base. 

I want to know how to choose the motor on the arm, wrist and claw, and point out what it is, the formula or something. The base is not used

Answer 1

According to the problem description, the design functions like a rotary table and is commonly used in the fourth axis of the machine tool. When selecting a motor, calculate the torque first, and then look at other requirements. Since there is no arm length, the arm length is taken by 100mm, and the reduction ratio of the reducer is taken by 10. The torque calculated without considering efficiency is 0.49N*M, and the selected motor torque is greater than 0.49 after calculating efficiency.

Set the torque, and then choose whether to step or servo. One look at the beat requirements, the speed of the stepper motor is up to 1000 rpm, the servo is generally up to 5000 rpm, the second is the positioning accuracy requirements, the step has a loss of steps and does not have the encoder problem, but the price is cheap, the encoder can be installed externally. Generally, if the requirements are not high, the step is preferred, and the servo is selected if the step cannot be met.

Answer 2

Hello, in fact, the most important thing in choosing a motor is to first calculate how much the equipment movement of your design needs to carry, and calculate the torque required. Then choose the right motor according to the control accuracy and control method you need.

Generally speaking, the accuracy and three-ring control of servo DC brushless motor are relatively good, which is very suitable for a series of operations such as grabbing and rocking.

Answer 3

If the response speed and large load are not required, a stepper motor is used, otherwise a brushless motor or a DC motor can be used, and there is really no requirement to steer.

Answer 4

Two major elements of stepper motor selection: torque matching and inertia matching

1. Torque matching:

a. Safety factor: Considering the calculation error and assembly accuracy, more than 2 times the safety rate should be guaranteed.

b. The maximum speed considering the stepper torque attenuates with the increase of speed, and the necessary torque must be below the motor running curve when selecting the motor.

2. Inertia matching:

a. The load moment of inertia should not exceed 10 times the motor moment of inertia.

b. When the inertia ratio is too large, the overshoot and recoil during starting and stopping also become larger, which will affect the starting and stabilization.

c. When the load inertia is too large, the inertia loaded into the motor shaft needs to be reduced.