System and method for object and operator profiling in an object detection system in a saw

• US 10,105,863 B2
• Filed: 03/04/2016
• Issued: 10/23/2018
• Est. Priority Date: 03/12/2015
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH, Robert Bosch Tool Corporation (Robert Bosch GmbH)
• Original Assignee: Robert Bosch GmbH, Robert Bosch Tool Corporation (Robert Bosch GmbH)
• Inventors: Ramaswamy, Bharadwaja Maharshi, Laliberte, Eric
• Primary Examiner(s): Williams, Alexander Oscar
• Application Number:
  US15/060,742
• Publication Number:
  US 20160263762A1
• Time in Patent Office: 963 Days
• Field of Search: 700160
• CPC Class Codes: B23D 45/06 with a circular saw blade arranged underneath a stationary work-table
• CPC Class Codes: B23D 45/065 with the saw blade carried by a pivoted lever
• CPC Class Codes: B23D 59/001 Measuring or control devices, e.g. for automatic control of work feed pressure on band saw blade measuring in general G01; controlling in general G05
• CPC Class Codes: B26D 5/005 Computer numerical control means
• CPC Class Codes: B26D 7/22 Safety devices specially adapted for cutting machines safety devices in general F16P
• CPC Class Codes: G05B 19/182 characterised by the machine tool function, e.g. thread cutting, cam making, tool direction control G05B19/21 - G05B19/40 take precedence
• CPC Class Codes: G05B 2219/36311 Machining mode selection, pocket, grooving, raster, area, profile
• CPC Class Codes: G05B 2219/49159 Avoid pinching of persons between moving and fixed part

Abstract

A method for operating an object detection system in a saw produces profiles for materials used in work pieces. The method includes operating a motor in the saw to move an implement and cut a work piece formed from a predetermined material, recording, a sensing signal produced in the object detection system during contact between the work piece and the implement, generating a detection profile for the material of the work piece based on the recorded sensing signal, storing, the detection profile in a memory in the saw, and operating the saw and the object detection system using the detection profile to distinguish between contact of the implement with a work piece formed from the predetermined material and contact of the implement with a portion of a body of an operator.

Claims

1. A method for operating an object detection system in a saw comprising:

operating a motor in the saw to move an implement;

engaging, with the implement in the saw, a work piece formed from a predetermined material while operating the motor to move the implement;

recording, with a controller, a sensing signal produced in the object detection system during the engaging of the work piece and the implement;

disabling, with the controller, an implement reaction mechanism in the saw during the recording to prevent triggering of the implement reaction mechanism during the recording;

generating, with the controller, a detection profile for the material of the work piece based on the recorded sensing signal;

storing, with the controller, the detection profile in a memory in the saw; and

operating the saw and the object detection system using the detection profile with the implement reaction mechanism being enabled to distinguish between contact of the implement with a work piece formed from the predetermined material and contact of the implement with a portion of a body of an operator.

2. The method of claim 1, the generating of the detection profile further comprising:

recording, with the controller, the sensing signal from a capacitive sensor in the saw;

identifying, with the controller, an amplitude of a first spike in the recorded sensing signal from the object detection system corresponding to a time at which the work piece engages the implement;

identifying, with the controller, a difference between the amplitude of the first spike in the recorded sensing signal and a predetermined threshold for the amplitude of a second spike that is generated in the sensing signal in response contact between the implement and the portion of the body of the operator; and

generating, with the controller, the detection profile corresponding to a range of amplitudes around the amplitude of the first spike, the range of amplitudes not including the predetermined threshold for the amplitude of the second spike.

3. The method of claim 1, the generating of the detection profile further comprising:

recording, with the controller, the sensing signal from a capacitive sensor in the saw;

identifying, with the controller, a time duration of a first spike in the recorded sensing signal from the object detection system beginning at a time at which the work piece engages the implement;

identifying, with the controller, a difference between the time duration of the first spike in the recorded sensing signal and a predetermined threshold for a time duration of a second spike that is generated in the sensing signal in response contact between the implement and the portion of the body of the operator; and

generating, with the controller, the detection profile corresponding to a range of time durations around the time duration of the first spike, the range of time durations not including the predetermined threshold for the time duration of the second spike.

4. The method of claim 1, the generating of the detection profile further comprising:

recording, with the controller, the sensing signal from an infrared sensor in the saw;

identifying, with the controller, a first frequency response for a detected infrared signal recorded from the work piece while the work piece engages the implement;

identifying, with the controller, a difference between the first frequency response in the recorded sensing signal and a predetermined second frequency response that is generated in the sensing signal in response to a detected infrared signal corresponding to the portion of the body of the operator; and

generating, with the controller, the detection profile corresponding to a frequency response range around first frequency response, the frequency response range not including the predetermined second frequency response.

5. A method for operating an object detection system in a saw comprising:

generating with a capacitive sensor in a predetermined contact location of the saw a capacitance signal in response to contact between the capacitive sensor a hand of an operator of the saw, the predetermined contact location including the capacitive sensor being at least one of a rip fence, a rail, or an adjustment handle in the saw that the hand of the operator contacts during operation of the saw, the predetermined contact location not being on an implement of the saw;

identifying, with the controller, a capacitance level of the hand of the operator based on the capacitance signal from the capacitive sensor;

modifying, with a controller, a detection threshold level for identification of contact between the operator and the implement in the saw in response to the capacitance signal from the capacitive sensor; and

operating with the controller the object detection system in the saw with the modified detection threshold level for detection of contact between the hand of the operator and the implement.

6. The method of claim 5, the modification of the detection threshold level further comprising:

increasing, with the controller, the detection threshold level in response to the capacitance level of the hand being greater than the default capacitance level.

7. The method of claim 6 further comprising:

detecting, with the object detection system, contact with a work piece generating a spike in a sensing signal exceeding a default detection threshold level and being less than the modified detection threshold level; and

continuing operation of the saw in response to the spike in the sensing signal being less than the modified detection threshold level.

8. The method of claim 5, the modification of the detection threshold level further comprising:

decreasing, with the controller, the detection threshold level in response to the capacitance level of the hand being less than the default capacitance level.

9. The method of claim 5 further comprising:

operating, with the controller, an implement reaction mechanism in the saw in response to the object detection system identifying contact between the hand of the operator and the implement using the modified detection threshold.