Positioning Unit Torque Control for EV Charging Contact Force

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Solution Overview

Problem

Existing positioning units for electric vehicles, such as buses, face challenges in maintaining a consistent contact force with charging stations due to varying vehicle heights and loading conditions, leading to increased manufacturing and operating costs, especially when using sensor-based solutions.

Innovation Solution

A positioning unit with an articulated arm device and a drive system that includes an adjustment drive and a spring device, where the adjustment drive is controlled by an electric motor to maintain a constant contact force regardless of the relative distance between the charging contact and the contact surface, using torque control to adapt the force effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sensor-based control is used to maintain contact force, then contact force consistency is improved, but manufacturing and operating costs increase

Engineering Contradiction:
Improvecontact force consistencyVSAvoidmanufacturing and operating costs
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces sensor-based electronic control with a purely mechanical solution using a spring device that directly generates and maintains contact force. The spring's elastic properties provide automatic force regulation without requiring sensors, controllers, or complex electronics, thereby maintaining contact force consistency while reducing manufacturing and operating costs.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The spring device serves itself by using its inherent elastic properties to automatically regulate and maintain contact force. The system self-adjusts to varying vehicle heights and loading conditions through the spring's natural compression and extension, without requiring external control systems, sensors, or active intervention.

Inventive Principle:
Principle #25Self-service

2Reliability

If the positioning unit is designed for a defined contact height, then contact force can be maintained, but adaptability to different vehicle heights is reduced

Engineering Contradiction:
Improvecontact force maintenanceVSAvoidadaptability to different vehicle heights
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent employs a dynamic spring device that can automatically adapt its compression state to different vehicle heights and loading conditions. The spring's elastic deformation allows the positioning unit to maintain consistent contact force across varying distances, transforming a static design into a dynamic, adaptive system that responds to changing conditions.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring device changes its physical state (compression and extension) in response to varying vehicle heights and loading conditions. By allowing the spring to compress or extend within its elastic range, the system maintains optimal contact force parameters despite changes in the distance to the charging contact surface.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the contact force is increased to ensure secure connection, then connection reliability is improved, but wear and maintenance requirements increase

Engineering Contradiction:
Improveconnection reliabilityVSAvoidservice life and maintenance intervals
Core Design Contradiction:
ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The spring device provides continuous mechanical feedback through its elastic properties. As the charging contact approaches or moves away from the charging surface, the spring automatically adjusts its compression state, maintaining optimal contact force without excessive pressure. This self-regulating feedback mechanism ensures reliable connection while preventing excessive wear through controlled force application.

Inventive Principle:
Principle #23Feedback

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 solution allows for reliable and consistent electrical connections across different vehicle heights and loading conditions, reducing maintenance and operational costs by using a brushless electric motor and a self-locking spindle drive, ensuring extended service life and reduced maintenance intervals.

Implementation Method 1

The drive device has an adjustment drive for forming an adjustment force acting on the articulated arm device and a spring device which interact with the adjustment drive mechanically

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

the adjustment drive has a control device and an electric motor which can be controlled by means of the control device, the adjustment drive being designed in such a way that a torque of the electric motor can be detected by the control device

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentEP3433124B1Positioning unit and contacting method
Publication Date: 2021.04.07 SCHUNK TRANSIT SYST GMBH
  • EP3433124B1 patent drawingFigure 1~2
  • EP3433124B1 patent drawingFigure 3~4
  • EP3433124B1 patent drawingFigure 5~6

AI summary

The invention relates to a positioning unit (10) and a method for forming an electrically conductive connection between a stationary charging station and a vehicle, in particular an electric bus or similar, wherein an electrical charging contact of the positioning unit can be moved relative to a charging contact surface (11) and contacted with same by means of the positioning unit, wherein the positioning unit has an articulated arm device (12) and a drive device for driving the articulated arm device, wherein the charging contact can be positioned between a contact position (37) for power transmission and a retracting position (36) for power interruption by means of the articulated arm device, wherein the drive device has an adjustment drive (13) for forming an adjustment force acting on the articulated arm device and a spring device (29) mechanically cooperating with the adjustment drive, wherein a contact force can be formed on the charging contact surface by the adjustment drive, wherein the adjustment drive has a control device and an electric motor (43), which can be actuated by the control device, wherein the adjustment drive is designed in such a way that a torque of the electric motor can be detected by the control device, wherein the contact force can be controlled by the control device in accordance with the torque of the electric motor.