Motion Control Acceleration Limiting via Friction Modeling
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Solution Overview
Problem
Conventional motion control systems set maximum acceleration manually, often underestimating the system's capabilities due to neglecting viscous friction, resulting in slower point-to-point moves.
Innovation Solution
A system that models torque over time, considering both Coulomb and viscous friction, to determine the maximum acceleration that can be achieved without violating mechanical constraints, and uses this to generate motion profiles for faster transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If maximum acceleration is set manually based on presumed mechanical limitations, then the system is simple to operate, but the move time increases due to underestimating system capabilities
Solution Approach 1:
The system automatically determines maximum acceleration by modeling torque characteristics and friction effects, eliminating the need for manual configuration. The motion control system performs self-testing or calculation to identify the true maximum acceleration capability, thereby reducing move time without requiring user expertise in friction modeling or torque analysis.
Solution Approach 2:
The system performs preliminary characterization of the motion system by modeling torque over time and determining friction parameters before actual operation. This preliminary analysis establishes the true maximum acceleration capability, which is then used to optimize motion profiles for faster positioning without violating mechanical constraints.
2Productivity
If maximum acceleration is increased to achieve faster moves, then productivity improves, but mechanical constraints may be violated causing reliability issues
Solution Approach 1:
The system changes the parameter determination approach from fixed manual values to dynamic values based on actual system characteristics. By modeling torque as a function of time and velocity, and incorporating friction parameters, the system identifies the true maximum acceleration that maintains reliability while enabling faster operation.
Solution Approach 2:
The system uses feedback from torque modeling and friction analysis to determine the optimal maximum acceleration. The motion control system continuously monitors system response and adjusts motion profiles to stay within mechanical constraints while maximizing speed, ensuring both productivity and reliability.
3Device complexity
If viscous friction is neglected in maximum acceleration calculation, then the calculation is simpler, but the determined acceleration is lower than the true maximum capability
Solution Approach 1:
The system replaces complex manual friction analysis with automated computational modeling. The motion control system uses software-based torque modeling that incorporates viscous friction effects through mathematical relationships, eliminating the need for manual approximation while accurately determining maximum acceleration capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for faster point-to-point moves by accurately determining the maximum acceleration, considering the system's true capabilities and varying torque conditions in different operating regions.
Implementation Method 1
The torque model includes a model of the combined Coulomb friction and speed-dependent viscous friction
Implementation Method 2
The torque model includes a model of the combined Coulomb friction and speed-dependent viscous friction
Data Source
AI summary
A maximum acceleration identification system determines a suitable maximum acceleration for transitioning a given motion/motor system to a target position or velocity, taking the friction of the motion system into consideration. The maximum acceleration determined by the maximum acceleration identification system can then be used by the motion control system as the acceleration limit for generating motion profiles. Thus, motion profiles can be generated that are closer to the true maximum acceleration supported by the motion system without violating the mechanical and electrical constraints of the system as characterized in part by the viscous friction, resulting in a more time-optimal move. In some embodiments, the maximum acceleration identification system can automatically set the maximum acceleration of the control system's profile generator to be equal to the derived value, thereby eliminating the need for the maximum acceleration to be selected and set by the system designer.