Robot Servo Feedforward Control for Phase-Aligned Tracking
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Solution Overview
Problem
Existing technologies fail to effectively address the phase inconsistency and high-frequency noise in velocity feedforward signals, leading to reduced trajectory tracking accuracy and position overshoot in robot servo systems.
Innovation Solution
A servo control system with a command delay module is introduced to process position commands, reducing phase difference by delaying the transmission of position signals, combined with differential processing and low-pass filtering to smooth velocity feedforward signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If velocity feedforward control is implemented by differentiating position command, then trajectory tracking accuracy is improved, but high-frequency noise and phase lag are introduced
Solution Approach 1:
The patent applies preliminary action by pre-calculating velocity feedforward values through a lookup table based on preset acceleration and deceleration profiles. Instead of differentiating the position command in real-time (which introduces noise), the system prepares velocity values in advance during system initialization or operation pauses, storing them for direct retrieval during execution. This eliminates the need for real-time differentiation while maintaining accurate velocity feedforward control.
Solution Approach 2:
The patent replaces the complex, noise-prone real-time differentiation operation with a simple lookup table retrieval mechanism. The lookup table acts as a pre-computed, disposable data structure that provides accurate velocity values without requiring ongoing mathematical operations. This substitution eliminates high-frequency noise generation while maintaining the benefits of velocity feedforward control.
2Stability of the object's composition
If low-pass filter is introduced to reduce high-frequency noise, then signal smoothness is improved, but phase lag increases
Solution Approach 1:
The patent eliminates the need for low-pass filtering by performing velocity calculation in advance during system initialization or operation pauses, rather than in real-time. The pre-calculated velocity values are stored in a lookup table and directly retrieved during operation. This approach provides smooth velocity signals without introducing the phase lag that would result from real-time filtering operations.
Solution Approach 2:
The patent replaces the mechanical signal processing chain (differentiation followed by low-pass filtering) with a computational lookup table approach. Instead of using mathematical operations and filters that introduce phase delays, the system uses pre-computed data retrieval, which provides smooth signals instantaneously without phase lag.
3Measurement precision
If velocity feedforward gain is increased to improve tracking accuracy, then position overshoot increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating velocity feedforward values with optimal gain characteristics during system initialization or operation pauses. The lookup table is populated with velocity values that inherently account for optimal gain scheduling, allowing the system to achieve high tracking accuracy without the position overshoot that would result from uniformly high velocity feedforward gain during dynamic transitions.
Data Source
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AI summary
A servo control method, apparatus (700, 800), and system (600), a robot (900), and a readable storage medium (902). The servo control method is executed by the servo control system (600). The servo control system (600) comprises a command interpolation module (610), a velocity command determination module (640), a command delay module (620), a position controller (630), and a velocity controller (650). The servo control method comprises: when a command interpolation module (610) receives a position command signal, a command delay module (620) determines a delay duration corresponding to the position command signal (102); a velocity command determination module (640) determines a velocity feedforward command signal based on the position command signal (104); the velocity command determination module (640) transmits the velocity feedforward command signal to a velocity controller (650) (106); and the command delay module (620) transmits the position command signal to a position controller (630) in a delayed manner based on the delay duration (108).