GB2515795A

GB2515795A - Payload measurement system

Info

Publication number: GB2515795A
Application number: GB201312017A
Authority: GB
Inventors: Adam Johnson Lambert; David Balfour
Original assignee: Caterpillar SARL
Current assignee: Caterpillar SARL
Priority date: 2013-07-04
Filing date: 2013-07-04
Publication date: 2015-01-07
Also published as: GB201312017D0; WO2015000665A1

Abstract

A machine comprising a power-source, a frame and a walking beam 202, where the beam 202 has a front and a rear end 206, 208 respectively and the beam and is mounted on the frame; a payload carrier capable of movement is attached to the frame and beam. Of a plurality of sensors 214 that are mounted on the beam and which are configured to generate a signal indicative of shear forces acting on the beam, at least one of the sensors is positioned at the rear end and at least one at the front end. A controller communicatively coupled to the sensors is configured to estimate a weight of the payload on the machine based upon shear forces acting on the beam. Further disclosures include both a system and a method of payload measurement for a machine. The machine or the system may have two sensors positioned on opposing sides of the beams front end and/or the beams rear end. The plurality of sensors of the machine or system may include at least one of a strain sensor and a load cell. The machine, system or method may be configured to notify an operator of the estimated payload weight.

Description

PAYLOAD MEASUREMENT SYSTEM

Technical Field

100011 The present disclosure relates to a payload measurement system, and morc specifically to a system and method for estimating weight of a payload on a machine.

Background

100021 Current methods for measuring a weight of a payload on a machine, such as, for example, an articulated truck, make use of a strain sensor mounted on a walking beam of the machine. The strain sensor measures a shear force acting on the walking beam. More specifically, a single strain sensor is positioned at an apex region of the walking beam proximate to a hitch of the walking beam. Use of the single strain sensor may not be reliable as failure of the single strain sensor may lead to failure of the overall system. In addition, the apex region of the walking beam may not always experience maximum magnitude of the shear force when the machine is loaded.

100031 These methods may thus lead to inaccurate measurement of the weight of the payload on the machine causing an operator to overload the machine.

Overloading of the machine may further lead to structural failures in the machine, causing an overall decrease in performance of the machine. Also, inaccurate measurement of the weight of the payload on the machine may cause the operator to under load the machine in some circumstances. Under loading of the machine may prevent the machine from being utilised at its full capacity resulting in decreased productivity and increased cost.

100041 Hence, there is a need for an improved system to monitor the weight of the payload associated with the machine.

Summary of the Disclosure

10005] In one aspect of the present disclosure, a payload measurement system for a machine is provided. The system includes a walking beam, associated with the machine, having a front end and a rear end. The system also includes a plurality of sensors mounted on the walking beam such that at least one of the plurality of sensors are positioned at the front end and at least one of the plurality of sensors are positioncd at the rear end. Each of the plurality of sensors is configured to generate a signal indicative of shcar forces acting on the walking beam. The system thither includes a controller communicably coupled to the plurality of sensors and is configured to estimate a weight of the payload on the machine based on the shear forces acting on the walking beam.

10006] Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

Brief Description of the Drawings

10007] Figure 1 is an exemplary machine, according to one embodiment of the

present disclosure;

10008] Figure 2 is an exploded view of a walking beam mounted on a frame of the machine; 10009] Figure 3 is a perspective view of the walking beam with a plurality of sensors; 10010] Figure 4 is another perspective view of the walking beam with a cover member; and 10011] Figure 5 is a flowchart of a method of operation of a payload measurement system.

Detailed Description

10012] Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or the like parts. Figure 1 illustrates an exemplary machine 100, according to one embodiment of the present disclosure.

More specifically, the machine 100 is an articulated truck. A person of ordinary skill in the art will appreciate that the machine 100 depicted in the accompanied figures is merely on an exemplary basis. It should be noted that the disclosure can be applied to any number of different types of wheeled machines used in industries including, but not limited to, construction, transportation, agriculture, forestry, waste management and the like.

100131 Referring to Figure 1, the machine 100 may have a front section 102 and a rear section 104. The front section 102 may be provided with a front frame and/or chassis 106. An operator cabin 108 maybe provided on the front frame 106 of thc front section 102. Thc operator cabin 108 may housc various controls of the machine 100. An enclosure 110 may be provided on the front section 102 which may house a power source (not shown). The power source may providc power to the machine 100 for mobility and/or other operational needs. Thc power source may include for example, a diesel engine, a gasoline engine, a gaseous fuel powered engine such as a natural gas engine, a combination of known sources of power or any other type of power source apparent to one skilled in the art. The power source may alternatively include a non-combustion source of power such as a fuel cell, a power storage device, an electric motor, or other similar mechanism. The front section 102 may further include a front wheel set 112. The front wheel set 112 may include wheels for manoeuvring of the machine 100 on ground.

100141 The rear section 104 of the machine 100 may be provided with a rear frame and/or chassis 114. The rear section 104 of the machine 100 may include a payload carrier 116 provided on the rear frame 114. The payload carrier 116 may be configured to carry a payload from onc location to another. Furthcr thc rear section 104 may include a centre wheel set 118 and a rear wheel set 120. The front and rear sections 102, 104 may be linked to each other by an articulation joint 122. The articulation joint 122 may permit relative movement between the front and rear sections 102, 104 about a vertical axis, enabling the machine 100 to be steered. The articulation joint 122 may also permit roll about a longitudinal axis minimising stresses on the front frame 106 and/or the rear frame 114 and maximising wheel contact and traction. Additionally, elements of a powertrain (not shown) like a torque converter, transmission inclusive of gearing, one or more drive shafts, differentials and other known elements of the powertrain may be provided on the machine 100 to transmit power from the power source to the front, centre and/or rear wheel sets 112, 118, 120.

100151 Referring to Figure 2, the centre and rear wheel sets 118, 120 may be connected to the rear frame 114 through a walking beam 202. The centre and rear wheel sets 118, 120 are not shown in Figure 2 for the purpose of clarity. The walking beam 202 may be formed as a substantially triangular shaped structure haying an apex 204, a front end 206 and a rear end 208. The centre and rear wheel sets 118, 120 may be connected to the walking beam 202 at the front and rear ends 206, 208, respectively. The walking beam 202 may be made of any suitable metal using any known manufacturing process like casting, forging, and so on. Further, the shape, size, dimensions and material of the walking beam 202 may be modified according to system design and requirements.

100161 Additionally, a suspension member 210 may be provided between the centre wheel set 118 and the front end 206, and the rear wheel set 120 and the rear end 208 respectively. The suspension member 210 may be any one or a combination of springs, telescopic suspension, pneumatic suspension, hydraulic suspension andlor any other suitable suspension member known in the art. The suspension member 210 may dampen shocks received by the centre and rear wheel sets 118, 120 while rolling on the ground which may otherwise be transmitted to the walking beam 202 and/or the rear frame 114. The walking beam 202 may be pivotally connected to the rear frame 114 through a hitch 212 provided at the apex 204 of the walking beam 202.

100171 The present disclosure relates to a payload measurement system configured to estimate a weight of the payload on the machine 100 based on shear forces acting on the walking beam 202. Referring to Figures 2 and 3, a plurality of sensors 214 may be mounted on the walking beam 202. The plurality of sensors 214 may be configured to generate a signal indicative of the shear forces acting on the walking beam 202. The plurality of sensors 214 may include any one or a combination of strain sensors and/or load cells known to one skilled in the art. For example, the sensor 214 may be a foil or wire type strain sensor, film type strain sensor, semiconductor strain sensor, bonded resistance strain sensor, capacitive strain sensor, hydraulic load cell, pneumatic load cell, strain gauge load cell or any other sensor configured to detect and/or measure strain.

100181 The plurality of sensors 214 may include at least one sensor 214 positioned at the front end 206 of the walking beam 202. Further, at least one of the plurality of sensors 214 may be positioned at the rear end 208 of the walking beam 202. In the illustrated embodiments, as shown in Figure 3, two sensors 214 are positioned at each of the front and rear ends 206, 208. More specifically, the two sensors 214 arc positioncd on opposing inner side facc 216 and outer sidc face 218 of thc front and rear ends 206, 208 of the walking beam 202 respectively. It should be noted that the plurality of sensors 214 are located in a region on the front and rear ends 206, 208 of the walking beam 202 which may experience maximum magnitude of the shear force. For example, arrows 302 shown in Figure 3 are indicative of a direction of the shear force acting at the front and rear ends 206, 208 of the walking beam 202 when the payload carrier 116 is loaded with the payload. Accordingly, the plurality of sensors 114 are positioned along the direction of the shear force acting in the region of the front and rear ends 206, 208 of the walking beam 202.

100191 Further, each of the plurality of sensors 214 may be angularly oriented relative to the walking beam 202 in order to be in cooperation with the shear force acting at the respective end of the walking beam 202. The plurality of sensors 214 may be externally affixed to the inner and outer side surfaces 216, 218 of the front and rear ends 206, 208 of the walking beam 202 by any known fastening method like bolting, riveting, clamping, welding, adhesion and the like.

The positioning of the plurality of sensors 114 on the front and rear ends 206, 208 of the walking beam 202 in cooperation with the direction of the shear force allows maintaining higher accuracy while determining the magnitude of the shear forces.

10020] Use of more than one sensor 214 in the system may substantially reduce the possibility of undesirable noise associated with prior systems making use of a single sensor 214. For example, the single sensor 214 mounted at the apex 204 of the walking beam 202 may give accurate readings of the payload when the machine 100 may be operating on a flat level ground. 1-lowever, when an operator steers the machine 100, the walking beam 202 may have an additional twisting force, including a positive force and a negative force, acting on it. This twisting force may cause the single sensor 214 to detect this force as a contributory factor in a change of the weight of the payload. 1-lence, in this situation, the single sensor 214 may provide an inaccurate reading of the weight of the payload.

100211 In the present disclosure, when the walking beam 202 twists on steering of the machine 100, depending on a direction of the steer, the positive force may be detected by the sensor 214 positioned on the outer side surface 218 of the front end 206 of the walking beam 202. The sensor 214 directly opposite on the inner side surface 216 of the front end 206 of the walking beam 202 may detect the negative force. Simultaneously, an equal and opposite pair of positive and negative forces may act on the rear end 208 of the walking beam 202.

Accordingly, the positive force may be detected by the sensor 214 positioned on the inner side surface 216 of the rear end 208 of the walking beam 202. The sensor 214 directly opposite on the outer side surface 218 of the rear end 208 of the walking beam 202 may detect the negative force. The positive force and the negative force may cancel or negate each other, and so in this ease, the estimated weight of the payload is not affected by the twisting force.

100221 The plurality of sensors 214 may be communicably coupled to other components present on the machine 100 like the power source, a controller (not shown), and so on with one or more harness 222. The harness 222 may include one or a combination of wires such as, for example, metallic wires or cables, optic fibre cables, and the like. The harness 222 may be configured to provide power to the phirality of sensors 214 from the power source. The harness 222 may further be configured to transmit signals indicative of the shear forces acting on the walking beam 202 from the plurality of sensors 214 to the controller. As shown in Figures 2 and 3, support members 224 may be provided on the wallung beam 202 along a length of the harness 222. The support members 224 may be configured to restrict movement and securely hold the harness 222 in place on the walking beam 202 during operation of the machine 100. The support members 224 may be any one or a combination of mechanical fasteners including, but not limited to, clamps, rings, brackets, adhesives, mounting pads, straps, and the like.

In one embodiment, the harness 222 may be concealed within the walking beam 202 by routing the harness 222 internally within the walking beam 202.

100231 As shown in Figure 4, a cover member 226 may be provided on thc walking beam 202. The cover member 226 may be configured to at least partially enclose the plurality of sensors 214 and!or the harness 222. The cover member 226 may protect the plurality of sensors 214 andior the harness 222 from debris, water, dust, sand, mud, extreme temperatures and mechanical damages like snapping of the harness 222, physical impacts to the sensors 214, and the like. The cover member 226 may be formed as a single or a multi piece component in the form of panels made of sheet metal or polymer. In the illustrated embodiment, the cover member 226 is a multi piece component made of sheet metal. Different pieces of the cover member 226 have different shapes and sizes to enable each piece of the cover member 226 to be appropriately affixed at a required location on the walking beam 202. It should be noted that the shape, size and dimensions of the cover member 226 may be appropriately selected according to the system design and requirements. The cover member 226 may be affixed to the walking beam 202 by any known mechanical fastening methods including, but not limited to, bolting, riveting, clamping, welding and adhesion.

100241 As explained earlier, the plurality of sensors 214 may be communicably coupled to the controller through the harness 222. The controller may be configured to receive the signals indicative of the shear forces acting on the walking beam 202 from the plurality of sensors 214. Based on the signals received from the plurality of sensors 214, the controller may be configured to estimate the weight of the payload on the machine 100. For example, a change in the magnitude of the shear forces acting on the wallung beam 202 may result in a change of one or more electrical properties of each of the plurality of sensors 214.

This change of the electrical properties of each of the plurality of sensors 214 may be proportional to the magnitude of the shear forces acting on the walking beam 202. Accordingly, each of the plurality of sensors 214 may be configured to generate the signal indicative of the magnitude of the shear force. The signals from each of the plurality of sensors 214 may be received by the controller which may be further configured to estimate the weight of the payload on the machine based on these signals.

100251 In one embodiment, the controller may be communicably coupled to a display device (not shown) provided in the operator cabin 102. The display device may be any known display device known in the art like a LED device, a LCD device, a CRT monitor, a touchscreen device, etc. The display device may be configured to display and notify the operator of the machine 100 of the weight of the payload on the machine 100 estimated by the controller. In one embodiment, the controller may be communicably coupled to a control station located remotely with respect to the machine 100. In such an embodiment, the controller may be configured to notify the operator and/or site manager present at the control station of the weight of the payload on the machine 100 estimated by the controller.

Industrial Applicability

10026] The working of the payload measurement system will now be described in detail. Figure 5 shows a method 500 of working of the payload measurement system. At step 502, at least one of the plurality of sensors 214 may be mounted at the front end 206 of the walking beam 202. At step 504, at least one of the plurality of sensors 214 may be mounted at the rear end 208 of the walking beam 202.

100271 At step 506, the controller may receive the signal indicative of the shear force acting on the walking beam 202 from each of the plurality of sensors 214.

At step 508, based on the signal received from each of the plurality of sensors 214, the controller may estimate the weight of the payload on the machine 100 based on the shear forces acting on the walking beam 202. The controller may be further configured to notif' the operator of the machine 100 of the estimated weight of the payload on the machine 100 through the display device.

100281 While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof.

Claims

claims What is claimed is: 1. A payload measurement system for a machine, the system comprising: a walking beam associated with the machine, the walking beam having a front end and a rear end; a plurality of sensors mounted on the walking beam, at least one of the plurality of sensors being positioned at the front end and at east one of the plurality of sensors being positioned at the rear end, each of the plurality of sensors being configured to generate a signal indicative of shear forces acting on the walking beam; and a controller communicably coupled to the plurality of sensors, the controller configured to estimate a weight of the payload on the machine based on the shear forces acting on the walking beam.
2. The system of claim 1, wherein at least two of the plurality of sensors are positioned on opposing sides of the front end of the walking beam.
3. The system of claim 1, wherein at least two of the plurality of sensors are positioned on opposing sides of the rear end of the walking beam.
4. The system of claim 1, wherein the plurality of sensors are affixed to the walking beam using mechanical fasteners.
5. The system of claim 1, wherein the plurality of sensors includes at least one of a strain sensor and a load cell.
6. The system of claim 1 further comprising a support member for a harness associated with the plurality of sensors, the support member configured to hold the harness on a surface of the walking beam.
7. The system of claim 6 fUrther comprising a cover member at least partially enclosing at least one of the plurality of sensors and the harness, the cover member configured to protect the plurality of sensors and the harness from debris and damage.
8. The system of claim 1, wherein each of the plurality of sensors is angularly oriented relative to the walking beam, the angular orientation of the each of the plurality of sensors being in cooperation with a direction of the shear force acting on the walking beam.
9. The system of claim 1, wherein the controller is fUrther configured to notify an operator of the estimated weight of the payload.
10. A method for measuring a payload on a machine, the method comprising: mounting at least one of a plurality of sensors at a front end of a walking beam associated with the machine; mounting at least one of the plurality of sensors at a rear end of the walking beam; receiving, from each of the plurality of sensors, a signal indicative of shear forces acting on the walking beam; and estimating a weight of the payload on the machine based on the shear forces acting on the walking beam.
11. The method of claim 10 further comprising notifying an operator of the estimated weight of the payload.
12. A machine comprising: a power source; a frame; a walking beam mounted on the frame, the walking beam having a front end and a rear end; a payload carrier attached to the frame and the walking beam, the payload carrier capable of movement; a plurality of sensors mounted on the walking beam, at least one of the plurality of sensors being positioned at the front end and at least one of the plurality of sensors being positioned at the rear end, each of the plurality of sensors being configured to generate a signal indicative of shear forces acting on the walking beam; and a controller communicably coupled to the plurality of sensors, the controller configured to estimate a weight of the payload on the machine based on the shear forces acting on the walking beam.
13. The machine of claim 12, wherein at least two of the plurality of sensors are positioned on opposing sides of the front end of the walking beam.
14. The machine of claim 12, wherein at least two of the plurality of sensors are positioned on opposing sides of the rear end of the walking beam.
15. The machine of claim 12, wherein the plurality of sensors includes at least one of a strain sensor and a load cell.
16. The machine of claim 12 further comprising a support member for a harness associated with the plurality of sensors, the support member configured to hold the harness on a surface of the walking beam.
17. The machine of claim 16 further comprising a cover member at least partially enclosing at least one of the plurality of sensors and the harness, the cover member configured to protect the plurality of sensors and the harness from debris and damage.
18. The machine of claim 12, wherein each of the plurality of sensors is angularly oriented relative to the walking beam, the angular orientation of the each of the plurality of sensors being in cooperation with a direction of the shear force acting on the walking beam.
19. The machine of claim 12, wherein the controller is further configured to notitSr an operator of the estimated weight of the payload.