Railway Car Slip Control Using Adhesion Indices
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional controlling devices for railway electric cars face difficulties in detecting and controlling slipping/sliding phenomena during high-speed travel, as the low rates of change of wheels' speeds and small speed deviations make it challenging to distinguish between normal acceleration and slipping/sliding states.
Innovation Solution
A controlling device with a slipping/sliding controlling unit that calculates adhesion level indices using rotation speeds of electric motors, generating a torque command value to inhibit slipping or sliding, including a reference rotation speed calculator, adhesion level index generators, and a torque command value generator, allowing for appropriate control without additional rotation speed information from non-drive shafts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional slip controlling systems use rates of change of wheels' speeds and speed deviation to detect slipping, then slipping can be detected in regular railway systems, but slipping cannot be reliably detected during high-speed travel where these parameters show minimal changes
Solution Approach 1:
The patent changes the detection parameters from rates of change of speed and speed deviation to adhesion level indices calculated directly from rotation speeds. By using the formula that computes adhesion level index based on the difference between actual rotation speed and reference rotation speed, the system can detect slipping even when speed changes are minimal, as is the case during high-speed travel.
2Speed
If torque is increased to improve acceleration, then wheels may spin free and adhesion coefficient decreases, but if torque is decreased to prevent spinning, then acceleration performance deteriorates
Solution Approach 1:
The patent implements a feedback control mechanism where the adhesion level index is continuously calculated from rotation speed data and fed back to adjust the torque command value. When slipping is detected (adhesion level index decreases), the torque is automatically reduced to prevent wheel spin. When adhesion is good, normal torque commands are applied to maintain acceleration performance. This closed-loop feedback system dynamically balances acceleration and adhesion stability.
Data Source
AI summary
Provided is a controlling device for a railway electric car, the controlling device being able to detect a slipping/sliding phenomenon during, in particular, high-speed travel and to exercise slipping/sliding control in an appropriate manner. A slip controlling unit 1 includes a first adhesion level index generating unit and a second adhesion level index generating unit. In a normal slipping state in which an acceleration changes instantaneously, torque control is exercised by using a first adhesion level index generated by the first adhesion level index generating unit based on an acceleration deviation and a speed deviation. In a slipping state during high-speed travel, because the acceleration deviation and the speed deviation are small, torque control is exercised by using a second adhesion level index generated by multiplying the first adhesion level index by a gain equal to or smaller than 1 generated by the second adhesion level index generating unit.