Acceleration Control Device for Vibration-Free Velocity Transitions
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Solution Overview
Problem
Conventional acceleration/deceleration control methods generate discontinuous acceleration, leading to vibrations when a target-velocity change command is input during acceleration, as they fail to reflect velocity changes promptly and maintain continuity in acceleration.
Innovation Solution
An acceleration/deceleration control device that generates a command acceleration and velocity to reach a target velocity, using a command generating unit, residual-velocity calculating unit, differential-velocity calculating unit, and acceleration-reduction-start-timing determining unit to create an acceleration reduction curve, ensuring continuity by reducing command acceleration when residual velocity exceeds differential velocity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a velocity command is generated using an ideal acceleration/deceleration curve from a data table, then the velocity command can be calculated simply and accurately, but when a target-velocity change command is input during acceleration, the acceleration becomes discontinuous and vibrations are excited
Solution Approach 1:
The system dynamically adjusts the acceleration command by introducing an acceleration reduction curve that modifies the ideal acceleration profile in real-time. When a target-velocity change is detected, the command generating unit reduces the command acceleration smoothly using the acceleration reduction curve, preventing discontinuities while maintaining the overall acceleration trajectory.
Solution Approach 2:
The invention changes the acceleration parameter by introducing a reduction factor based on the acceleration reduction curve. This curve modifies the command acceleration parameter dynamically, ensuring smooth transitions when target velocity changes occur during acceleration, thereby maintaining acceleration continuity while adapting to new velocity targets.
2Reliability
If the command acceleration is reduced smoothly using an acceleration reduction curve, then acceleration continuity is maintained, but the velocity change response time increases
Solution Approach 1:
The system applies partial acceleration reduction only when necessary - specifically when a target-velocity change command is input during acceleration. The acceleration reduction curve is applied selectively rather than continuously, reducing command acceleration only to the extent needed to maintain smooth transitions, thereby minimizing the time penalty while ensuring acceleration continuity.
3Measurement precision
If the acceleration reduction curve is generated based on residual velocity and differential velocity comparison, then the velocity changes are reflected accurately, but the control complexity increases
Solution Approach 1:
The command generating unit continuously monitors the relationship between residual velocity and differential velocity, and adjusts the command acceleration accordingly. When residual velocity exceeds differential velocity, the system activates the acceleration reduction curve; otherwise, it maintains the ideal acceleration profile. This feedback mechanism ensures accurate velocity change reflection while keeping the control logic relatively simple through clear conditional thresholds.
Data Source
AI summary
A residual-velocity calculating unit calculates a residual velocity that corresponds to a velocity increment when an acceleration is reduced from a current command acceleration to zero according to an acceleration reduction curve. A differential-velocity calculating unit calculates a differential velocity vs=v0-vn, which is a difference between a target velocity v0 and a current velocity command for every command generation period. An acceleration-reduction-start-timing determining unit compares the residual velocity to the differential velocity for determining whether acceleration reduction starts. When a condition that the residual velocity is equal to or larger than the differential velocity is satisfied, the acceleration-reduction-start-timing determining unit determines the start of the acceleration reduction and starts to reduce the command acceleration according to the acceleration reduction curve generated by the command generating unit.