Plugging and plugging override control apparatus

• US 4,529,919 A
• Filed: 01/05/1983
• Issued: 07/16/1985
• Est. Priority Date: 01/05/1983
• Status: Expired due to Term

• Current Assignee: Towmotor Corporation (Caterpillar Incorporated)
• Original Assignee: Towmotor Corporation (Caterpillar Incorporated)
• Inventors: Pickering, William, Melocik, Grant C.
• Primary Examiner(s): Weldon, Ulysses
• Application Number:
  US06/455,722
• Time in Patent Office: 923 Days
• Field of Search: 318/373, 318/374, 318/258, 318/383, 318/379, 318/375, 318/376, 318/329
• US Class Current: 318/373
• CPC Class Codes: B60L 2220/46 Wheel motors, i.e. motor connected to only one wheel
• CPC Class Codes: B60L 3/0023 Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
• CPC Class Codes: B60L 7/006 Dynamic electric braking by reversing current, i.e. plugging
• CPC Class Codes: B60L 7/12 for vehicles propelled by dc motors

Abstract

A control system (28) is provided for controlling the supply of power to a motor (12) having an armature (34) and a plugging diode (38) connected across the armature (34), including a circuit (14) for producing direction command signals, a circuit (98) for generating digital motor power command signals, a circuit (16) for sensing a plugging condition and generating a plug signal, a microprocessor (46) for generating one of a plurality of pulse trains during typical plugging conditions and for automatically overriding the generation of the one pulse train and generating other of the plurality of pulse trains during special plugging conditions. By automatically providing the override feature during the special plugging conditions, the disadvantage of manual override in prior control systems is obviated.

Claims

1. Apparatus (10) for controllably energizing a motor (12) of a vehicle, said vehicle having a power source (30) and said motor (12) having an armature winding (34) and a field winding (36), comprising:

an accelerator pedal (102) moveable to a plurality of motor speed command positions;

generating means (98) for producing a predetermined plurality of incremental coded digital motor power command signals in response to the position of said accelerator pedal (102);

direction sensing means (14) for producing forward and reverse digital logic direction signals in response to a selected direction of vehicle travel;

a plugging diode (38) connected in parallel with said armature winding (34) of said motor (12) and being forward biased in response to plugging of said motor (12) and reverse biased in the absence of plugging of said motor (12);

plug sensing means (16) for producing a digital logic plug signal in response to said plugging diode (38) being forward biased, wherein said plug sensing means (16) includes a voltage divider (88) serially connected between said plugging diode (38) and circuit common, an amplifier (80) having a first input connected to said voltage divider, a second input connected to circuit common, and an amplifier output, and a logic gate (94) having an input connected to said amplifier output and an output adapted to deliver the said digital logic plug signal;

a plurality of directional contacts (50, 52, 54,

     56) connected between said armature winding (34) and said power source (30) and adapted to selectively control the direction of current flow through said armature winding (34);

a power coupling element (40) serially connected between said motor (12) and said power source (30); and

, programmed microprocessor means (18) for;

(1) receiving said predetermined plurality of incremental coded digital motor power command signals, said forward and reverse digital logic direction signals, and said digital logic plug signal;

(2) controllably actuating said direction contacts (50, 52, 54,

     56) in response to receiving one of said forward and reverse digital logic direction signals;

(3) periodically storing the digital value of said forward and reverse digital logic direction signal currently being received;

(4) producing and delivering respective predetermined motor power control signals to said power coupling element (40) in response to receiving said coded digital motor power command signals and said forward and reverse digital logic direction signals and to being free from receiving said digital logic plug signal;

(5) continuing to produce and deliver respective predetermined motor power control signals to said power coupling element (40) in response to receiving said digital logic plug signal and said coded digital motor power command signals and to continuing to receive the one of said forward and reverse digital logic direction signals last stored prior to receiving said digital logic plug signals; and

,

(6) producing and delivering only a predetermined one of said motor power control signals to said power coupling element (40) in response to receiving said digital logic plug signal, any of said plurality of coded digital motor power command signals, and the other of said forward and reverse digital logic direction signals different from the one of said digital logic direction signals last stored prior to receiving said digital logic plug signal.

2. Apparatus (10), as set forth in claim 1, wherein said direction sensing means (14) includes a manual direction control switch (62) having a forward and reverse contact position, and a pair of logic inverter gates (68, 70) each having an input connected to a respective one of said forward and reverse contact positions and an output connected to said microprocessor means (18).

3. Apparatus (10), as set forth in claim 1, including a second motor (12'"'"') having a second armature winding (34'"'"') and field winding (36'"'"'), and a second plugging diode (38'"'"') connected in parallel with said second armature winding (36'"'"') and being forward biased in response to plugging of said second motor (12'"'"') and reverse biased in the absence of plugging of said second motor (12'"'"'), and wherein said plug sensing means (16) produces said digital logic plug signal in response to at least one of said plugging diodes (38, 38'"'"') being forward biased.

4. Apparatus (10), as set forth in claim 3, wherein said plug sensing means (16) includes a second voltage divider (88'"'"') serially connected between said second plugging diode (38'"'"') and circuit common, and a second amplifier (80'"'"') having a first input connected to said second voltage divider (88'"'"'), a second input connected to circuit common, and an output, said logic gate (94) having a second input connected to said second amplifier output.

5. Apparatus (10) for controllably energizing first and second motors (12, 12'"'"') of a vehicle, said vehicle having a power source (30) and said first and second motors (12, 12'"'"') having respective armature windings (34, 34'"'"') and field windings (36, 36'"'"'), comprising:

an accelerator pedal (102), moveable to a plurality of motor speed command positions;

generating means (98) for producing a predetermined plurality of incremental coded digital motor power command signals in response to the position of said accelerator pedal (102);

direction sensing means (14) for producing forward and reverse digital logic direction signals in response to a selected direction of vehicle travel;

a first plugging diode (38) connected in parallel with said armature winding (34) of said first motor (12) and being forward biased in response to plugging of said first motor (12) and reverse biased in the absence of plugging of said first motor (12);

a second plugging diode (38'"'"') connected in parallel with said armature winding (36'"'"') of said second motor (12'"'"') and being forward biased in response to plugging of said second motor (12'"'"') and reverse biased in the absence of plugging of said second motor (12'"'"');

plug sensing means (16) for producing a digital logic plug signal in response to at least one of said plugging diodes (38, 38'"'"') being forward biased;

a plurality of directional contacts (50, 52, 54,

     56) connected between said armature winding (34) and said power source (30) and adapted to selectively control the direction of current flow through said armature winding (34);

a power coupling element (40) serially connected between said motor (12) and said power source (30); and

, programmable microprocessor means (18) for;

(1) receiving said predetermined plurality of incremental coded digital motor power command signals, said forward and reverse digital logic direction signals, and said digital logic plug signal;

(2) controllably actuating said direction contacts (50, 52, 54,

     56) in forward and reverse digital logic direction signals;

(3) periodically storing the digital value of said forward and reverse digital logic direction signal currently being received;

(4) producing and delivering respective predetermined motor power control signals to said power coupling element (40) in response to receiving said coded digital motor power command signals and said forward and reverse digital logic direction signals and to being free from receiving said digital logic plug signal;

(5) continuing to produce and deliver respective predetermined motor power control signals to said power coupling element (40) in response to receiving said digital logic plug signal and said coded digital motor power command signals and to continuing to receive the one of said forward and reverse digital logic direction signals last stored prior to receiving said digital logic plug signal; and

,

(6) producing and delivering only a predetermined one of said motor power control signals to said power coupling element (40) in response to receiving said digital logic plug signal, any of said plurality of coded digital motor power command signals, and the other of said forward and reverse digital logic direction signals different from the one of said digital logic direction signals last stored prior to receiving said digital logic plug signal; and

, wherein said plug sensing means (16) includes a first voltage divider (88) serially connected between said first plugging diode (38) and circuit common, a first amplifier (80) having a first input connected to said first voltage divider, a second input connected to circuit common, and an output, and a logic gate (94) having a first input connected to said first amplifier output and an output connected to said microprocessor means (18); and

a second voltage divider (88'"'"') serially connected between said second plugging diode (38'"'"') and circuit common, a second amplifier (80'"'"') having a first input connected to said second voltage divider (88'"'"'), a second input connected to circuit common, and an output, said logic gate (94) having a second input connected to said second amplifier output.