Patent EP0151322A2 successfully refreshed from Google Patents.
EP0151322A2
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EP
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Working depth control system for vehicle with ground working implement
Assignee: Deere and Co
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Filing: 1983-03-21
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Granted: —
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Expires: 2003-03-21
Abstract
Abstract A tractor (10) includes a hitch (26) for pulling a ground- working implement. A hydraulic cylinder (34) is extensible and retractable to lower and raise the implement. A control system (50) senses operating parameters, including wheel slip, engine speed, draft force and implement or rockshaft position. Error signals are derived from the sensed wheel slip, engine speed and draft force and correspond set point signals. The error signals are combined into a composite or combined error signal. The larger of (a) the combined error signal and (b) a separately determined position error signal, is selected and converted to a pulsewidth modulated valve control signal which is applied to a control valve (42) which then actuates the cylinder to move the implement to reduce the magnitude of the selected error signal. Certain set point signals are derived from the corresponding parameter signals themselves.
Inventors
- 👤 Gordon K Wiegardt
- 👤 Thomas William Hanks
- 👤 Carl Edwin Kittle
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-28 14:12
CPC Classifications
A; A01; A01B; A01B67/00; A01B63/00; A01B63/02; A01B63/10; A01B63/111; A01B63/1117
Claims Analysis
Total Claims: 21
Claim 1
Independent Claim
156 words
A working depth control system for a vehicle having means for attaching a ground-penetrating implement and an actuator for raising and lowering the implement in response to a control signal (HCVO), comprising wheel slip means (62, 64, 108, 118) generating a slip error signal (SERR), further means (68, 66, 150 or 38, 58,226,228) generating an additional error signal (RERR or DRAFT-LCOM) pertaining to a controlled parameter of the machine system comprising the vehicle, the attaching means and the implement, and means (226, 228, 264) deriving the control signal conjointly from the slip error signal and the additional error signal, characterised in that the slip error signal (SERR) as well as the additional error signal (RERR or DRAFT-LCOM) is formed as the difference between an actual value signal (SLIP, ENGS or DRAFT) and a corresponding set-point signal (SSET, RSCL-THRS or LCOM) and the control signal (HCVO) is derived from a linear combination of the error signals (LERR).
Claim 2
Dependent Claim
156 words
A working depth control system for a vehicle having means for attaching a ground-penetrating implement and an actuator for raising and lowering the implement in response to a control signal (HCVO), comprising wheel slip means (62, 64, 108, 118) generating a slip error signal (SERR), further means (68, 66, 150 or 38, 58,226,228) generating an additional error signal (RERR or DRAFT-LCOM) pertaining to a controlled parameter of the machine system comprising the vehicle, the attaching means and the implement, and means (226, 228, 264) deriving the control signal conjointly from the slip error signal and the additional error signal, characterised in that the slip error signal (SERR) as well as the additional error signal (RERR or DRAFT-LCOM) is formed as the difference between an actual value signal (SLIP, ENGS or DRAFT) and a corresponding set-point signal (SSET, RSCL-THRS or LCOM) and the control signal (HCVO) is derived from a linear combination of the error signals (LERR).
Claim 3
Dependent Claim
34 words
A control system according to claim 1, characterised in that the additional error signal is an engine speed error signal (RERR) indicative of a difference (RSCL-THRS-ENGS) between a sensed and a set-point engine speed.
Claim 4
Dependent Claim
105 words
A control system according to claim 2, characterised by an engine speed sensor (68) coupled to the engine for generating a sensed engine speed signal indicative of the actual speed of the engine; means (66) for generating a reference engine speed signal (RSCL) representing the set-point speed of the vehicle engine; means for generating a threshold engine speed signal (THRS) representing a predetermined difference between the sensed and reference engine speed signals; and means (150, 160) for generating the engine speed error signal (EERR, RERR) as an arithmetic function of sensed engine speed signal, the reference engine speed signal and the threshold engine speed signal.
Claim 5
Dependent Claim
27 words
A control system according to claim 3, characterised by means (158) for maintaining the engine speed error signal (EERR, RERR) not less than a predetermined minimum value.
Claim 6
Dependent Claim
27 words
A control system according to claim 3, characterised by means (148) for maintaining the threshold engine speed signal (THRS) not less than a predetermined minimum value (THLL).
Claim 7
Dependent Claim
63 words
A control system according to claim 2, characterised by operator-controlled means (58) for generating a load command signal (LCOM) representing a set-point draft force; means (188) for generating a draft limited signal (ELIM) as a function of the load command signal; and means (216-218) for limiting the magnitude of the engine speed error signal (RERR) to the magnitude of the draft limit signal.
Claim 8
Dependent Claim
56 words
A control system according to claim 2, characterised by operator-adjustable load command means (58) for generating a load command signal (LCOM) representing the set-point draft force; and means (119, 156, 194-204) for momentarily modifying the slip error (SERR) and engine speed error (RERR) signals in response to a predetermined operator-induced change in the load command signal.
Claim 9
Dependent Claim
58 words
A control system according to claim 3, characterised in that the reference engine speed generator means includes speed control means (14) for controlling the vehicle engine and sensing means (66) coupled-to the speed control means for sensing the operational status of the speed control means and for converting the sensed status of the reference engine speed signal (RSCL).
Claim 10
Dependent Claim
31 words
A control system according to claim 8, characterised by means (132, 150) for limiting raising of the implement in response to a predetermined change in the reference engine speed signal (RSCL).
Claim 11
Dependent Claim
42 words
A'control system according to claim 1, characterised in that the additional error signal is a draft error signal derived from a difference (DRAFT-LCOM) between a sensed draft force produced by interaction between the implement and the ground and a set-point draft force.
Claim 12
Dependent Claim
39 words
A control system according to any of claims 2 to 9 and claim 10 characterised in that the linear combination of error signals (LERR) combines the slip error signal, the engine speed error signal and the draft error signal.
Claim 13
Dependent Claim
52 words
A control system according to claim 10 or 11, characterised by operator-adjustable load command means (58) for generating a load command signal (LCOM) establishing the set-point draft force, and means (119, 194-204) for momentarily modifying the slip error signal (SERR) in response to a predetermined operator-induced change in the load command signal.
Claim 14
Dependent Claim
30 words
A control system according to claim 12, characterised in that the modifying means (119) comprises means for incrementally and periodically decreasing the slip error signal (SERR) in a non-linear manner.
Claim 15
Dependent Claim
143 words
A control system according to any of claims 1 to 13, characterised in that the wheel slip means comprises a ground speed sensor (69) for sensing vehicle ground speed (TVEL), a wheel speed sensor (62) for sensing the rotation speed of the driven wheel and means (104) for converting the rotation speed to a wheel travel velocity (WVEL), divider means (108) for generating a slip signal (SLIP) corresponding to a quotient derived by dividing the difference between the travel velocity and the ground speed by the travel velocity, means (204) for generating a slip set-point signal (SSET) representing a reference value of wheel slippage; and comparator means (118) for producing the slip error signal (SERR) when the slip signal exceeds the slip set-point signal, the magnitude of theslip error signal being proportional to a difference between the slip and the slip set-point signals.
Claim 16
Dependent Claim
74 words
A control system according to any of claims 1 to 13, characterised in that the wheel slip means includes sensor means (62, 69, 108) for generating a wheel slip signal (SLIP) representing slip of the driven wheels, means (204) for generating a slip set-point signal (SSET) representing a predetermined amount of wheel slippage and difference means (118) for generating the slip error signal representing a difference between the wheel slippage and slip set signal.
Claim 17
Dependent Claim
44 words
A control system according to claim 15, insofar as dependent on claim 12, characterised by means (194-204) for redetermining the slip set-point signal (SSET) based on a wheel slip signal (SLIP) generated a predetermined time interval after adjustment of the load command means (58).
Claim 18
Dependent Claim
55 words
A control system according to claim 15 or 16, characterised by means (110-112) for maintaining the slip error signal (SERR) not less than a predetermined minimum value to prevent a reduction in the magnitude of the combined signal and a corresponding increase in implement depth were the slip error to decrease below the minimum value.
Claim 19
Dependent Claim
62 words
18 A control system according to claim 15, 16 or 17, characterised in that the slip set-point signal generating means (204) comprises: filter means (114) for generating a filtered slip signal (FSLP) derived from periodically generated values of the slip signal (SLIP), and means (204) for adding a predetermined increment to the filtered slip signal to form the slip set-point signals (SSET).
Claim 20
Dependent Claim
54 words
A control system according to any of claims 1 to 18, characterised in that the connecting means comprises a movable hitch (26) coupled between the implement and the vehicle, the actuator (34) being coupled between the hitch and the vehicle and being capable of moving the hitch, thereby to raise and lower the implement.
Claim 21
Dependent Claim
73 words
A control system according to any of claims 1 to 19, characterised in that the actuator comprises a hydraulic cylinder and piston (34) for raising the implement in response to fluid communciated thereto; and electrohydraulic valve means (42) responsive to the control signal (HVCO) for controlling the rate of fluid flow between a fluid pressure source and the cylinder as a function of the magnitude of the linear combination of error signals (LERR).
References Cited (Backward Citations)
No citation records indexed.
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