Winch Arm Control on Ski Groomers to Counter Yawing Torque
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Solution Overview
Problem
Existing crawler vehicles for preparing ski runs face issues with yawing torque when the cable direction does not align with the vehicle's center of gravity, limiting their effective use.
Innovation Solution
A crawler vehicle equipped with a winch and an actuating system featuring two actuators that can transmit torques in opposite directions around a swiveling arm, allowing for controlled rotation and locking of the arm position, managed via a hydraulic circuit and joystick for manual operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the arm is left free to orient itself when the cable is under tension, then the arm automatically aligns with the cable portion outside the arm, but this causes the cable force to apply a yawing torque to the crawler vehicle when the force direction does not pass through the barycentre
Solution Approach 1:
The control device applies a preliminary counteracting torque through the actuating system to offset the harmful yawing torque generated by cable tension. The system proactively counteracts the unwanted rotational effect by applying an equal and opposite torque through the actuators, preventing the vehicle from yawing rather than allowing it to occur and then correcting it.
Solution Approach 2:
The control device continuously monitors the arm angle relative to the frame and the yawing torque magnitude, then automatically adjusts the actuating torque to compensate for the harmful effect. This closed-loop feedback system ensures the arm remains in the desired position while counteracting the yawing torque generated by cable tension.
2Object-affected harmful factors
If automatic compensation of yawing torque is applied to eliminate the harmful effect, then the yawing torque is compensated, but this limits possible beneficial uses of the yawing torque
Solution Approach 1:
The actuating system provides dynamic control of the arm position and yawing torque compensation, allowing the operator to select between different operating modes (automatic compensation, manual control, or disabled). This dynamic adaptability enables the system to switch between eliminating harmful yawing effects and utilizing beneficial yawing torque for vehicle steering or position control as needed.
3Stability of the object's composition
If the arm is constrained to prevent yawing torque, then vehicle stability is improved, but the arm loses the ability to freely align with the cable direction
Solution Approach 1:
The patent replaces the traditional mechanical constraint system with an active control system using actuators and a control device. Instead of mechanically preventing arm movement through physical constraints, the system uses controlled torque application to maintain vehicle stability while preserving arm mobility and alignment capability through intelligent actuation.
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
Enables precise control over yawing torque, enabling the vehicle to maintain alignment with the cable and prevent unwanted yawing, enhancing operational stability and maneuverability.
Implementation Method 1
each actuator is a two-way flow hydraulic motor supplied with a pressure variable between a minimum and a maximum value
Implementation Method 2
when the cable is under tension the arm is left free to orient itself around the axis
Implementation Method 3
When the direction of the force exerted by the cable on the crawler vehicle does not pass through the barycentre of the crawler vehicle, said force applies a yawing torque to the crawler vehicle
Data Source
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AI summary
A crawler vehicle for the preparation of ski runs; the crawler vehicle (1) comprising: a frame (2); a winch (12) mounted on the frame (2) for selectively unwinding and winding a cable (13) that can be anchored to a point (14) outside the crawler vehicle (l); an arm (16), which is mounted swivelling with respect to the frame (2) around a determined axis (A2), and is configured to guide the cable (13); an actuating system (17) of the arm (16) around the determined axis (A2); a control device (18) of the actuating system (17) of the arm (16) for selectively setting one of the following operating modes when the cable (13) is under tension: allowing the free rotation of the arm (16) around the determined axis (A2); rotating the arm (16) around the determined axis (A2); locking the position of the arm (16) with respect to the frame (2).