Standstill Speed Control for Multi-Body Systems With Dead Zone Feedback
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Solution Overview
Problem
Existing speed control methods for multi-body systems face stability issues at standstill due to static friction, which is difficult to model accurately, leading to potential loss of stability and oscillations, especially when measurement noise is present.
Innovation Solution
A dead zone element is introduced in the speed control loop to suppress measurement noise, converting measurement speeds with noise into a dead zone speed that is zero within certain limits, thereby preventing destabilizing excitation and maintaining stability during standstill phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a speed controller determines manipulated variables to adjust actual speed to target speed using precise modeling, then control accuracy is improved, but device complexity increases due to mathematically complex models required to map dynamic behavior
Solution Approach 1:
The patent changes the parameter representation by using measured physical quantities (speeds, positions, accelerations) directly as feedback signals rather than relying on complex mathematical models. This transforms the control approach from model-based to measurement-based, reducing computational complexity while maintaining control accuracy.
Solution Approach 2:
The patent replaces the mathematical modeling approach with a direct measurement and feedback approach. Instead of using complex differential equations to model system dynamics, the system directly measures actual speeds and positions and uses these measurements for control, substituting mathematical complexity with physical measurement.
2Reliability
If exact modeling of friction is implemented to improve control stability, then reliability is improved, but device complexity increases due to difficulty in accurately predicting friction forces
Solution Approach 1:
The patent replaces complex friction modeling with direct measurement of actual system behavior. Instead of attempting to calculate friction forces through complex mathematical models, the system measures actual speeds and positions and uses these measurements to determine the necessary control actions, effectively bypassing the need for explicit friction modeling.
Solution Approach 2:
The system uses its own measured performance (actual speeds, positions, accelerations) to automatically adjust control without requiring external friction models. The measured values themselves serve as the basis for control decisions, making the system self-regulating without needing complex environmental or material property models.
3Reliability
If measurement noise is filtered to improve control stability, then reliability is improved, but measurement precision deteriorates due to loss of useful signal information
Solution Approach 1:
The patent uses multiple measured values (speeds, positions, accelerations) simultaneously rather than relying on a single filtered signal. By using excess measurement information from different sources and time points, the system achieves noise rejection through redundancy rather than through filtering that would degrade signal quality.
Solution Approach 2:
The system implements continuous feedback using directly measured speeds and positions without intermediate filtering. The feedback loop uses raw measured values to continuously adjust control actions, allowing the system to naturally reject noise through the feedback mechanism itself rather than through signal processing that would compromise measurement precision.
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
The dead zone element effectively prevents loss of stability and oscillations by eliminating measurement noise, ensuring robust standstill control without requiring exact modeling of the multi-body system, and can be easily integrated into existing controller structures.
Implementation Method 1
static friction acts on the friction body
Data Source
Figure 1~5
Figure 3~6
Figure 4
AI summary
To ensure stable operation in a standstill control method for a multibody system (MBS) with at least one drive body (JA) and at least one friction body (JR) mechanically coupled to the drive body (JA), where static friction (µ) acts on the friction body (JR), the velocity of one of the bodies (JA, JR) of the multibody system (MBS) is determined as a measurement velocity (vmess) subject to measurement noise (nv) and converted in a dead zone element (101) to a dead zone velocity (vtot), wherein the dead zone velocity (vtot) is zero for measurement velocity (vmess) values above zero and below a positive dead zone limit (vtot,O) and is higher for measurement velocity (vmess) values above the positive dead zone limit (vtot,O). assumes the measurement speed (vmess),and the dead zone speed (vtot) is fed to a speed controller (Rn) as the actual speed (vist) for regulation.