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Sensors for articulated steering

Articulated vehicles have a pivot joint in its design, enabling the front of the vehicle to turn relative to the rear. Commonly seen in non-road-mobile-machinery ‘NRMM’, for example loaders and forest machinery. Vehicle-trailer combinations such as tractor-agriculture seed drill or tractor-road maintenance equipment can also be regarded as articulated vehicles if there is steering/feedback between the vehicle and trailer. Articulated steering connects the front and rear halves of a vehicle or mobile machinery so that the front and rear turns in a controlled and synchronized manner.

Articulated vehicles are more agile and easier to maneuver, making them ideal for small spaces, where precision is necessary and for increased safety and comfort for the operator. The agile steering also enables the rear wheels to follow the path of the front wheels, with less soil damage as a result, a common requirement for forestry and agricultural machinery.

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Sensor solutions

To control the movement of front and rear are position feedback signals necessary, this can be solved with different position sensors and designs.

A very robust and reliable sensor solution is to use cylinder sensors in the hydraulic cylinders that connect the front and rear of the vehicle. The integrated sensor is well protected from external stresses such as water, ice, dirt or debris that can be thrown towards the area. The sensor is also protected from mechanical forces that can arise when the front and rear are moving relative to each other.

The downside of using cylinder sensors is that the hydraulic cylinder needs to be designed and manufactured to enable incorporation of the sensor.

Rotary sensor ACW4 hall effect rotary position sensor

An alternative solution is to place a angular sensor in the joint between the front and rear, this is practical in vehicle-trailer combinations where there are no hydraulic cylinders connecting the two. In such case can an angular sensor with separate sensor housing and magnet be a suitable option, for example ACW4. The magnet can be mounted on the trailer and sensor housing on the vehicle, and as the sensor housing and magnet are not mechanically connected can the trailer be disconnected without additional steps to disconnect the sensor. Angular sensors can also be used as feedback-sensor on the trailer bogie, to ensure that the trailer co-tracks the vehicle.

Angular sensors offer a compact, low-cost and flexible solution, the downside is that it’s not as robust as cylinder sensors. Mounting and enclosures of the sensor need to be well designed to protect the sensor from external environmental and mechanical stresses.

If you want to know more, please don’t hesitate to contact us. What is the best solution for your application?