Motor Velocity Control via Acceleration Compensation
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Solution Overview
Problem
Existing motor velocity control methods for robots face inefficiencies due to reduced torque at high velocities, leading to low motor efficiency and potential torque mismatches when using dynamic equations for real-time torque calculation.
Innovation Solution
A method that generates a velocity profile based on user input, estimates acceleration using an acceleration-velocity graph, and compensates the profile in real-time to drive the motor to maximum velocity, avoiding torque exceedance by adjusting velocity sections such as acceleration and deceleration phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the motor is driven at high velocity regions beyond rated RPM, then motor velocity efficiency is improved, but the allowable torque decreases and the motor may be driven at torque exceeding allowable torque
Solution Approach 1:
The patent applies dynamics by making the velocity profile adjustable and adaptive rather than fixed. The compensation value is dynamically calculated based on actual motor torque and velocity feedback, allowing the system to optimize motor utilization across different operating conditions. This enables the motor to operate efficiently in high velocity regions while maintaining torque within allowable limits through real-time adjustments.
Solution Approach 2:
The patent changes the parameter of velocity profile by introducing a compensation value that modifies the original velocity profile. This compensation is calculated based on the ratio of actual torque to maximum torque and the difference between target and actual velocity. By dynamically adjusting the velocity profile parameter through compensation, the system enables safe operation in high velocity regions while preventing torque exceedance.
2Productivity
If a velocity profile compensation algorithm using dynamics is used to drive the motor to maximum velocity, then motor velocity efficiency is improved, but a complicated dynamic equation needs to be solved per control cycle
Solution Approach 1:
The patent extracts the essential compensation mechanism from the complex dynamic equation solving process. Instead of solving full dynamic equations, it extracts only the necessary torque-velocity relationship and uses a simplified compensation calculation based on torque ratio and velocity difference. This extraction maintains the benefits of dynamic compensation while eliminating the computational burden of solving complicated dynamic equations.
Solution Approach 2:
The patent uses a lightweight, computationally inexpensive compensation calculation method that can be executed quickly in each control cycle. The compensation value is calculated using simple arithmetic operations (multiplication, division, subtraction) rather than complex numerical solvers. This approach provides real-time adaptability without the heavy computational cost of full dynamic equation solving.
3Ease of manufacture
If the highest RPM of the motor is set to the rated RPM and velocity profile is generated based on rated RPM, then the motor is easily designed and conveniently controlled, but efficiency of motor velocity is considerably low
Solution Approach 1:
The patent prepares a compensation calculation mechanism in advance that can be applied to any velocity profile. The compensation value formula is pre-established based on torque-velocity characteristics, allowing the system to safely extend operation into high velocity regions without requiring redesign of the motor or control architecture. This preliminary preparation enables efficient motor utilization while maintaining design simplicity.
Solution Approach 2:
The patent makes the velocity profile dynamic and adaptive rather than fixed at rated RPM. The compensation mechanism allows the system to dynamically adjust the velocity profile based on actual motor performance and load conditions, enabling operation beyond rated RPM when appropriate while maintaining the simplicity of the original design. This dynamic approach bridges the gap between ease of design and velocity efficiency.
Data Source
AI summary
A motor velocity control apparatus and method in which the velocity of a motor to drive a joint of a robot is controlled. The method includes generating a velocity profile of the motor based on velocity profile generation data received from a user; judging whether one velocity section selected from velocity sections divided from the generated velocity profile corresponds to a high velocity region, where the high velocity region corresponds to an acceleration compensation section in which an acceleration section transitions to a constant velocity section; estimating an acceleration corresponding to the current velocity of the motor, upon judging that the velocity section corresponds to the high velocity region, the acceleration corresponding to the current velocity is estimated using an acceleration-velocity graph in the acceleration compensation section or a deceleration compensation section; compensating for the velocity profile using the estimated acceleration; and driving the motor using the compensated velocity profile.