Position measuring system for working machine

• US 7,831,362 B2
• Filed: 09/29/2003
• Issued: 11/09/2010
• Est. Priority Date: 10/02/2002
• Status: Expired due to Term

• Current Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Fujishima, Kazuo, Ishibashi, Hideto
• Primary Examiner(s): Mancho; Ronnie
• Application Number:
  US10/503,096
• Publication Number:
  US 20050080559A1
• Time in Patent Office: 2,598 Days
• Field of Search: 701/50, 701/26, 701/36, 701/29, 701/213, 701/214, 701/215, 701/35, 701/207, 172/2, 373/48, 374/14, 373/82, 37/91, 373/41, 340/426.18
• US Class Current: 701/50
• CPC Class Codes: E02F 9/2045 Guiding machines along a predetermined path for graders E02F3/841; machines for construction of roads E01C19/004
• CPC Class Codes: G01S 19/14 specially adapted for specific applications
• CPC Class Codes: G01S 19/23 Testing, monitoring, correcting or calibrating of receiver elements
• CPC Class Codes: G01S 19/47 the supplementary measurement being an inertial measurement, e.g. tightly coupled inertial
• CPC Class Codes: G01S 19/54 using carrier phase measurements; using long or short baseline interferometry

Abstract

The invention is intended to provide a position measuring system for a working machine, which can accurately measure the position of a monitoring point and can ensure high working efficiency even when measurement accuracy of a machine-equipped GPS has changed. A panel computer (45) computes the position of the monitoring point, which is set on an operating mechanism, in a three-dimensional space based on values measured by GPS receivers (43, 44) and angle sensors (21, 22, 23). When measurement accuracy of at least one of at least two GPS receivers lowers, the panel computer (45) corrects the computation for the position of the monitoring point based on a yaw angle measured by a gyroscope (25) for measuring the yaw angle of a machine body.

Claims

1. A position measuring system for a hydraulic excavator comprising a lower travel structure, an upper swing body swingably mounted to said lower travel structure and a front operating mechanism mounted to said upper swing body, the position measuring system comprising:

a first means for measuring three-dimensional positions disposed in said upper swing body and measuring positions of said upper swing body in a three-dimensional space when said first three-dimensional position measuring means is in a first state of measurement accuracy;

a second means for measuring three-dimensional positions disposed in said upper swing body and measuring positions of said upper swing body in a three-dimensional space independently of said first means when said second three-dimensional position measuring means is in a first state of measurement accuracy;

means for computing a position of a monitoring point in the three-dimensional space based on values measured by said first and second position measuring means;

means for measuring a yaw angle of said hydraulic excavator; and

display means,

wherein said position computing means computes the position of the monitoring point based on a coordinate system of said front operating mechanism when both said first and second three-dimensional position measuring means change from said first state of measurement accuracy, and

wherein, when the measurement accuracy of both said first and second three-dimensional position measuring means changes from said first state, movement of said upper swing body, which is movement of a front mechanism including swing movement is enabled, and said position computing means displays at said display means that travel of said lower travel structure is prohibited.

2. A position measuring system for a hydraulic excavator according to claim 1,

wherein said front operating mechanism has a plurality of rotatable members and angle sensors for measuring respective angles of the rotatable members, and

wherein said position computing means computes the position of the monitoring point by determining on said coordinate system of said front operating mechanism on the basis of a coordinate system of the machine body and values of the angle sensors.

3. A position measuring system for a hydraulic excavator according to claim 1,

wherein, when the measurement accuracy of at least one of said at least two three-dimensional position measuring means exceeds the predetermined value, said position computing means informs an operator that travel of said hydraulic excavator is enabled.

4. A position measuring system for a hydraulic excavator according to claim 1, further comprising:

said display means displaying the position of the monitoring point in accordance with a computation result of said position computing means,

wherein notices to be informed to the operator are displayed on said display means.

5. A position measuring system for a hydraulic excavator according to claim 1, further comprising:

data output means for outputting position data of the monitoring point obtained as the computation result of said position computing means;

data input means disposed in a position different from said hydraulic excavator and receiving the position data outputted from said data output means; and

second display means for displaying the position of the monitoring point in accordance with the position data received by said data input means,

wherein notices to be informed to the operator are displayed on said display means.

6. A position measuring system for a hydraulic excavator according to claim 1,

wherein said front operating mechanism comprises a plurality of rotatable members,

the monitoring point is set on said front operating mechanism,

said position measuring system further comprises angle measuring means for detecting respective angles between two of said plurality of members of said front operating mechanism, and

said position computing means computes the position of the monitoring point in the three-dimensional space based on values measured by said first and second position measuring means and said angle measuring means.

7. A position measuring system for a hydraulic excavator comprising a lower travel structure, an upper swing body swingably mounted to said lower travel structure and a front operating mechanism mounted to said upper swing body, the position measuring system comprising:

a first means for measuring three-dimensional positions disposed in said upper swing body and measuring positions of said upper swing body in a three-dimensional space when said first three-dimensional position measuring means is in a first state of measurement accuracy;

a second means for measuring three-dimensional positions disposed in said upper swing body and measuring positions of said upper swing body in a three-dimensional space independently of said first means when said second three-dimensional position measuring means are in a first state of measurement accuracy;

means for computing a position of a monitoring point on said front operating mechanism in the three-dimensional space based on values measured by said two position measuring means;

means for measuring a yaw angle of said hydraulic excavator; and

means receiving an output from said position computing means for informing an operator of a change in said first state of measurement accuracy,

wherein said position computing means computes the position of the monitoring point based on a coordinate system of said front operating mechanism when measurement accuracy of both said first and second three-dimensional position measuring means changes from said first state, and

wherein, said means receiving an output from said position computing means when both said first and second three-dimensional position measuring means change from said first state of measurement accuracy, informs an operator that travel of said lower travel structure is prohibited while movement of said upper swing body is enabled, and prohibits travel of said lower travel structure.

8. A position measuring system for a hydraulic excavator according to claim 7, wherein said means receiving an output from said position computing means when both said two three-dimensional position measuring means change from said first state, informs an operator that travel of said lower travel structure is prohibited through a speaker using voice.