Door Operator Control for Constant-Force Manual Opening
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Solution Overview
Problem
Existing door operators experience variable and surprising resistance during manual override, leading to an unpleasant user experience due to back driving and increased braking when users attempt to open doors faster than the predefined speed.
Innovation Solution
A motor-driven door operator system with a controller that adjusts its output mode to maintain a constant user force by assisting manual effort when the motor force drops below a threshold, transitioning between predefined and assisted opening modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the door operator maintains a pre-defined slow opening speed for safety, then safety is improved, but the opening speed is reduced
Solution Approach 1:
The door operator implements dynamic speed control by transitioning between two operational modes: a first mode that maintains a pre-defined slow opening speed for safety, and a second mode that enables faster opening when the user applies sufficient manual force. The controller dynamically switches between these modes based on the force applied by the user, allowing the opening speed to adapt to user needs while maintaining safety as the default state.
2Speed
If the user applies manual force to open the door faster, then the opening speed is improved, but the motor becomes back driven causing resistance
Solution Approach 1:
The controller continuously monitors the force applied by the user and the operational mode of the motor. When the user applies sufficient force to overcome the minimum threshold, the controller detects this input and switches the motor from the first mode (speed control) to the second mode (force assistance). This feedback mechanism ensures the motor does not create resistance by back driving, as the controller adjusts the motor output to match the user's manual force input.
Solution Approach 2:
The system changes the motor's operational parameters by switching between two distinct modes. In the first mode, the motor operates with speed control to maintain a pre-defined opening speed. In the second mode, the motor operates with force control to assist the user's manual force input. This parameter change allows the motor to adapt its behavior based on the user's actions, eliminating back driving resistance while enabling faster opening when needed.
3Ease of operation
If the motor provides constant force to assist manual opening, then ease of operation is improved, but speed control is reduced
Solution Approach 1:
The door operator implements dynamic mode switching based on user input. In the first mode, the motor provides speed control to maintain a pre-defined opening speed. When the user applies sufficient manual force, the system transitions to the second mode where the motor provides constant force assistance to ease manual opening. This dynamic adaptation allows the system to provide both speed control and ease of operation at different times, depending on user needs.
Solution Approach 2:
The controller uses feedback from the user's manual force input to determine when to switch between operational modes. When the detected force exceeds a threshold, the controller switches to force assistance mode to improve ease of operation. When the user releases force or applies less than the threshold, the controller returns to speed control mode. This feedback mechanism ensures the motor provides the appropriate type of assistance while maintaining overall speed control of the door opening process.
Data Source
AI summary
A door is coupled to a door operator assembly that includes a motor operable in a first mode of operation to open the door at a pre-defined speed. The first mode of operation is overridden in response to an output of the motor reaching a minimum threshold due to a force applied to the door. In the second mode of operation, the output of the motor is adjusted to assist manual opening of the door.