CROSS REFERENCE TO RELATED APPLICATIONS

This application is a National Stage of International Application No. PCT/CN2018/087909, filed on May 22, 2018, which claims priority to Chinese Patent Application No. 201710802292.4, filed on Sep. 7, 2017, both of which are hereby incorporated by reference in their entireties.

TECHNICAL FIELD

The present invention relates to the technical field of weight-bearing measurement, and more particularly to weight-bearing equipment and a weight-bearing measurement device and method for the weight-bearing equipment.

BACKGROUND

With gradual development of technologies, more and more weight-bearing movement devices have come into view. These weight-bearing movement devices have been accepted by the general users because they may bring convenience to people's lives and work. For example, the weight-bearing movement devices are relatively more popular balance car products that may meet the demands for short journeys of the users, or intelligent AGVs (Automated Guided Vehicles) for goods delivery, which may meet the demands for automatic goods carrying of factories.

A weight-bearing movement device has the characteristics of weight bearing and movement. For these two functions, the weight-bearing movement device needs to be equipped with various movement-related sensors to ensure its own normal weight bearing and movement and to prevent undesirable statuses.

Among these sensors, a weight sensor plays a very important role and may associate the two functions of weight bearing and movement, such that a movement control system of the weight-bearing movement device may control an output torque of a motor in accordance with the gravity and/or the mass of a borne object to further guarantee the movement smoothness of the weight-bearing movement device. This shows that the measurement accuracy of the weight sensor may directly affect control of the motor. For example, in the working process of a balance car, a motor control system should always pay attention to weight bearing of the balance car and send a reasonable PWM (Pulse-Width Modulation) control signal to the motor to control its working current which in turn controls the output torque of the motor.

A conventional weight-bearing measurement method is implemented based on the assumption that the gravity of the borne object is perpendicular to a deformable body of the weight sensor (i.e., the deformable body of the weight sensor is always in a horizontal status by default). Therefore, this measurement only considers deformation of the deformable body in a direction of gravity. When the weight-bearing movement device tilts during movement, the weight sensor is in a tilted status, such that accurate gravity or mass data of the borne object may not be obtained through this measurement method when a bearing face of the deformable body is no longer perpendicular to the gravity of the borne object. This may result in an excessively large or small output torque of the motor. Consequently, the weight-bearing movement device is unbalanced and ultimately may not work normally.

SUMMARY

An objective of an embodiment of the present invention is to provide a novel technical solution for measuring the gravity and/or the mass of a borne object such that the gravity and/or the mass of the object may be accurately measured when a bearing face of the borne object is tilted.

According to a first aspect of the present invention, there is provided a weight-bearing measurement device of weight-bearing equipment, comprising:

a weight sensor that is disposed on the weight-bearing equipment and comprises a deformable body and a bridge circuit, wherein the deformable body deforms under the action of gravity of a borne object, the bridge circuit comprises at least one resistance strain gauge that is disposed on the deformable body, and the bridge circuit is configured to generate an output voltage that represents the deformation under the action of an input voltage;

an acceleration sensor configured to detect acceleration components of the deformable body under the action of gravity of the borne object in a U direction, a V direction and a W direction, wherein the W direction is perpendicular to a bearing face of the deformable body, and the U direction, the V direction and the W direction are perpendicular to one another respectively; and

a processing unit configured to calculate the gravity and/or the mass of the borne object in accordance with the acceleration components in the U direction, the V direction and the W direction, the input voltage, the output voltage and conversion coefficients of the bridge circuit in the U direction, the V direction and the W direction, wherein the conversion coefficient is a constant that represents a proportional relation between a stress in a corresponding single direction and the generated output voltage.

According to a second aspect of the present invention, there is further provided a weight-bearing measurement method of weight-bearing equipment. A weight sensor and an acceleration sensor are disposed on the weight-bearing equipment.

The weight sensor comprises a deformable body and a bridge circuit. The deformable body deforms under the action of gravity of a borne object. The bridge circuit comprises at least one resistance strain gauge that is disposed on the deformable body. The bridge circuit generates an output voltage that represents the deformation under the action of an input voltage. The input voltage is a fixed voltage that is loaded at an input end of the bridge circuit.

The weight-bearing measurement method comprises:

acquiring acceleration components, detected by the acceleration sensor, of the deformable body under the action of gravity of the borne object in a U direction, a V direction and a W direction in case of weight bearing, wherein the W direction is perpendicular to a bearing face of the deformable body, and the U direction, the V direction and the W direction are perpendicular to one another respectively;

acquiring an input voltage of the bridge circuit and an output voltage of the bridge circuit in case of weight bearing; and

calculating the gravity and/or the mass of the borne object in accordance with the acceleration components in the U direction, the V direction and the W direction, the input voltage, the output voltage and conversion coefficients of the bridge circuit in the U direction, the V direction and the W direction,

wherein the conversion coefficient is a constant that represents a proportional relation between a stress in a corresponding single direction and the generated output voltage.

According to a third aspect of the present invention, there is further provided weight-bearing equipment. The weight-bearing equipment comprises a bearing body for bearing an object, a movement mechanism disposed below the bearing body, a motor configured to drive the movement mechanism to move, a motor control device, and the weight-bearing measurement device according to the first aspect of the present invention. The weight-bearing measurement device is disposed in the bearing body and configured to calculate the gravity and/or the mass of a borne object in case of weight bearing and to provide the calculated gravity and/or mass to the motor control device, such that the motor control device may adjust an output torque of the motor in accordance with the gravity and/or the mass.

The embodiments of the present invention have a beneficial effect that the weight-bearing measurement method and device detect the acceleration components of the deformable body under the action of gravity of the borne object in the perpendicular to one another respectively U direction, V direction and W direction through the acceleration sensor, such that the gravity and/or the mass of the borne object may be determined in accordance with a relationship between the output voltage of the bridge circuit and the gravity components of the borne object in the U direction, the V direction and the W direction. Thus, even if the deformable body is in a tilted status, the gravity and/or the mass of the borne object may be accurately measured in accordance with the weight-bearing measurement method and device provided by the embodiments of the present invention. Further, accurate gravity and/or mass data may be provided to the motor control device of the weight-bearing equipment for accurate movement control.

