Motorised Trolley Force-Sensing Control and Regenerative Braking
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Solution Overview
Problem
Manually driven wheeled trolleys face challenges with heavier loads, requiring significant physical effort and posing safety risks on slopes, while powered trolleys are difficult to operate delicately and require substantial operator skill.
Innovation Solution
A motorized trolley with electric drive wheels, electromechanical service brakes, auxiliary brakes, force-sensing couplings, and a controller that amplifies user input force and adjusts braking based on load sensors and IMU data for intuitive and safe operation, including regenerative braking and free-wheeling modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If manual driving is used, then the trolley structure is simple, but heavier loads require significant physical effort and pose safety risks
Solution Approach 1:
The patent replaces the purely mechanical manual driving system with an electromechanical system. Electric motors are integrated into the drive wheels to provide powered assistance, substituting human physical effort with electrical actuation while maintaining a relatively simple overall structure through direct-drive motor integration.
Solution Approach 2:
The drive motors serve multiple functions: they provide propulsion when the user pushes the trolley, provide regenerative braking to recover energy during downhill movement or deceleration, and can act as holding brakes to maintain position on slopes. This multi-functionality reduces the need for separate mechanical braking systems.
2Ease of operation
If powered trolleys with switch-type controls are used, then physical effort is reduced, but operator skill is required and delicate operations are difficult
Solution Approach 1:
The force-sensing couplings automatically detect and measure the user's pushing or pulling force on the handlebar, eliminating the need for manual throttle control or switch operation. The system self-regulates motor torque based on the sensed force, providing intuitive control that adapts to the user's natural physical input without requiring learned skills.
Solution Approach 2:
The force-sensing couplings provide continuous feedback about the user's applied force to the controller, which adjusts motor output in real-time. This closed-loop feedback system ensures that the motor assistance precisely matches the user's intent, enabling delicate operations through subtle force variations while maintaining simplicity.
3Loss of energy
If regenerative braking is used, then energy recovery is improved, but braking control complexity increases
Solution Approach 1:
The drive motors serve dual functions as both propulsion devices and regenerative braking devices. The same motor windings that generate torque for movement also generate electrical energy during regenerative braking by operating in generator mode. This eliminates the need for separate braking mechanisms and simplifies the overall control architecture.
Solution Approach 2:
The patent merges the propulsion system and braking system into a single integrated electromechanical system. The drive motors, force-sensing couplings, and battery management are combined into a unified control framework where the same hardware components perform both acceleration and deceleration functions, reducing overall system complexity.
4Ease of operation
If force-sensing couplings with load sensors are used, then user input is amplified, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical force amplification mechanisms (such as levers, pulleys, or hydraulic systems) with electronic force sensing and electrical torque amplification. The force-sensing couplings use electrical load sensors to detect user input, and the controller amplifies this signal to drive the motors, providing mechanical advantage through electrical means rather than mechanical multiplication.
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 motorized trolley reduces the effort required to move loaded trolleys, ensures safe operation on slopes, and allows for intuitive handling by amplifying user input force while maintaining control and safety through adaptive braking and torque adjustments.
Implementation Method 1
each force-sensing coupling comprising a resilient member and a load sensor for sensing forces applied by a user to the handlebar
Implementation Method 2
a respective electric drive motor drives each of the drive wheels
Implementation Method 3
an electromechanical service brake on each of the left and right drive wheels
Implementation Method 4
an auxiliary brake that mechanically biases at least one of the left and right drive wheels to a braked state
Implementation Method 5
the controller is configured, during braking of the motorised trolley, to perform regenerative braking by the drive motors
Data Source
AI summary
Respective electric drive motors (13a, 13b) drive left and right drive wheels (10a, 10b) having friction brakes, including an electromechanical service brake (31a, 31b) and an auxiliary brake (32a, 32b) mechanically biasing them to a braked state. An elongate handlebar (16) for user control is mounted via a pair of force-sensing couplings (17a, 17b) including a resilient member (18) and a load sensor (19) sensing forces applied by a user to the handlebar and transmitting respective load signals. A controller (37) receives the load signals and controls a current applied to the electric drive motors (13a, 13b) so as to amplify the force sensed by the force-sensing couplings and to generate a torque proportional to a force applied by the user to the handlebar and to actuate an electric release actuator of the auxiliary brake (32a, 32b) when the force applied by the user to the handlebar exceeds a threshold.