Self-Propelling Trolley Control With Free-Wheeling and Rocking
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Solution Overview
Problem
Users face difficulties in maneuvering trolleys, especially when pushing or pulling them uphill or downhill, due to high effort requirements and potential loss of control, which poses security risks, particularly for children's and liquid sample trolleys. There is a need for a self-propelled solution that reduces effort, allows rocking motion, and provides a free-wheeling mode while ensuring safety, cost-efficiency, and environmental friendliness.
Innovation Solution
A self-propelling trolley assembly equipped with a brushless electric motor having a stator with a number of poles not being an integer multiple of rotor poles, subdivided into magnetically and electrically identical subsets, and a control unit that implements feedback-assisted, free-wheeling, and rocking drive patterns using different voltage patterns to the motor, allowing precise control and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a conventional non-motorized trolley is used, then the construction is simple and cost-effective, but the user experiences high effort and potential loss of control when maneuvering uphill or downhill
Solution Approach 1:
The patent replaces the purely mechanical manual pushing/pulling system with an electric motor system that provides automated propulsion. The motorized drive unit substitutes human physical effort with electrical power, enabling the trolley to move uphill, downhill, and perform rocking motions without requiring user strength or manual force application.
Solution Approach 2:
The trolley becomes self-propelled through the electric motor system that autonomously provides the necessary propulsion force. The control system automatically regulates motor operation based on terrain conditions and user input, allowing the trolley to service itself by providing its own driving force without continuous manual intervention.
2Ease of operation
If a motorized system is added to reduce maneuvering effort, then ease of operation improves, but device complexity and cost increase
Solution Approach 1:
The electric motor system is designed to perform multiple functions: propulsion for moving the trolley uphill and downhill, rocking motion for soothing children or preventing sample settling, and free-wheeling mode for manual maneuvering when desired. This multi-functionality consolidates what would otherwise require separate mechanisms into a single motorized system, managing complexity while maximizing utility.
Solution Approach 2:
The control system dynamically adjusts motor operation based on real-time conditions, switching between different operational modes (propulsion, rocking, free-wheeling) as needed. The system adapts its behavior to match terrain requirements and user preferences, providing optimal performance across varying operating conditions without requiring fixed mechanical configurations for each function.
3Ease of operation
If the motor is continuously engaged for self-propulsion, then maneuvering effort is reduced, but energy consumption increases
Solution Approach 1:
The control system dynamically switches between motorized propulsion mode and free-wheeling mode based on user input and terrain conditions. When the trolley encounters flat surfaces or when manual maneuvering is preferred, the system disengages the motor and allows the trolley to coast or be manually pushed, significantly reducing energy consumption during portions of the journey where full motorized assistance is not required.
4Ease of manufacture
If a simple motor design is used, then manufacturing cost is reduced, but control precision and efficiency decrease
Solution Approach 1:
The patent employs a brushless direct current (BLDC) motor with electronic commutation instead of a traditional brushed motor or complex mechanical control system. This substitution of electronic control for mechanical commutation achieves precise control of motor operation, enables accurate positioning for rocking motions, and optimizes energy efficiency while maintaining relatively simple motor construction that is cost-effective to manufacture.
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 solution provides smooth, efficient, and safe operation with low cogging, precise control, and energy efficiency, enabling reduced effort in maneuvering, secure handling, and adaptable functionality including rocking and free-wheeling modes, while maintaining a robust and cost-effective design.
Implementation Method 1
at least one wheel which is driven by an electric motor, which electric motor is powered by said battery
Implementation Method 2
the electric motor is of a type in which the stator comprises a number of stator poles which is not an integer multiple of a corresponding number of rotor poles and in which the stator poles are subdivided into at least three magnetically and electrically identical subsets
Data Source
Figure 1
Figure 2
AI summary
Self-propelling trolley assembly(100), comprising a battery (156); at least one wheel (111,112) which is driven by an electric motor (151,152;1), which electric motor is powered by said battery; a rotation position or velocity sensor (9) arranged to sense a rotation position or rotation velocity of at least one trolley wheel (111,112); a user interface (153); and a control unit (150) arranged to regulate the electric motor based upon input from said user interface so as to affect a rotation of said wheel according to particular drive patterns. The invention is characterised in that the control unit is arranged to implement at least a feedback assisted propulsion drive pattern, based upon information read from said position or velocity sensor; a free-wheeling drive pattern; and a rocking drive pattern, in that all of said drive patterns are implemented using different drive voltage patterns to said electric motor, and in that the electric motor is of a type in which the stator (2) comprises a number of stator (2) poles (7) which is not an integer multiple of a corresponding number of rotor (3) poles and in which the stator poles are subdivided into at least three magnetically and electrically identical subsets (8) that are mounted one after the other around the angular direction of the electric motor.