Method and apparatus for safeguarding vehicles or devices moving in space.

The invention relates to a method and a device with the features of the preamble of claim 1 (US-A-3,493,920).

In a known method for measuring distance according to the ultrasonic echo principle, the reflected echo signal is supplied during an adjustable gating times to an evaluation electronics. In the area of ​​gate times are no distances recognizable (DE-A-3036081).

It is known to control the room, remote controlled or autonomous vehicles moving distance sensors, particularly ultrasonic sensors to install, to help avoid a collision with an obstacle. Such known sensors are serially clocked in order to avoid measurement errors. This requires each completing the measurement cycle of a sensor before the start of the measurement cycle of another sensor (EP-A-0052357).

The invention has for its object to provide a method and apparatus specified in the preamble of claim 1 is known, with which a higher level of security is achieved against a collision with obstacles.

To solve this object the features of claim 1 and a device according to the invention the features of claim 3 are provided in a method according to the invention.

The sensors are advantageously designed as ultrasonic sensors for transmitting and receiving ultrasonic signals and all of the same design. So it is not different sensors for short or long distances and / or trigger a warning signal or an emergency stop as used in the US-A-3,493,920.

According to the invention are all located on the vehicle distance sensors in an integrated system for common, time-synchronous triggering and measured quantity summarized. This includes the possibility of a collision with an obstacle located in the detection range of a prior art straight non-activated sensor.

By synchronous clocking for all sensors in a high sampling rate can be achieved, the higher vehicle speeds permits than before.

The reaction signal may cause a speed reduction or a stop of the vehicle, advantageously reduces the speed drops below a first, greater distance from an obstacle and an emergency stop falls below a second, smaller predetermined distance is triggered. Both distance thresholds are independently adjustable.

In addition, the measurement signals of the sensors can be used as reference signals for actively influencing the vehicle movement in the sense of obstacle avoidance, driving parallel to a wall or the like. Are utilized.

A constructive embodiment of a device according to the preamble of claim 3 is characterized in that the or each ultrasonic sensor is accommodated in a vehicle-mounted receiving apparatus according to all directions in predetermined angular ranges adjustable. Thus a space-scale surveillance of environment allows for obstacles.

This embodiment of the invention allows the replaceable, capacitively decoupled and individually angularly adjustable arrangement of one or more distance sensors on the vehicle.

The invention is explained in detail below with reference to schematic drawings of embodiments with further details. Show it:<ul><li>Fig. 1 a movable vehicle in the space in plan view, to which a plurality of ultrasonic sensors are arranged;</li><li>2 is a circuit diagram for interconnection of the sensors of Figure 1 for the common initiation and processing of the measurement signals..;</li><li>FIG. 3 is a structural design of a device for receiving a plurality of common ultrasonic sensors.</li></ul>

The vehicle 2 illustrated in FIG. 1 is for example a driverless transport vehicle, as eingeetzt in modern factories. On its front side the vehicle 2 is provided with a total of five ultrasonic sensors. 4 At the two sides of the vehicle 2 per two ultrasonic sensors 4 are arranged, while only one ultrasonic sensor 4 is provided at the back.

All ultrasonic sensors are designed to transmit and receive ultrasound signals without distinction short or long distance equal.

The main direction of travel of the vehicle 2 is indicated by the arrow. 6 In this forward direction of the arrangement of the ultrasonic sensors is so dense that the detection cone or "lobes" of the ultrasonic sensors 4 have overlap in the immediate vicinity of the vehicle, so that a complete monitoring field is formed already relatively close ahead of the vehicle. In each lobe 8 a engschraffierter area 10, a less closely hatched area 12 and a wide shaded area 14 is arranged. The boundary line 11 of the closely hatched area denotes a threshold that triggers a stop signal for the vehicle of the second The boundary line 13 of the less closely hatched area 12 designates a threshold at which a speed reduction signal for the vehicle 2 is activated.

The ultrasonic sensors 4 are clocked together triggered (measurement cycle), and its measurement signals are processed in a common circuit, which is schematically shown in Fig. 2.

In Fig. 2 with the reference numeral 20 is a timing module for the time-synchronous initiation of the measurement cycles of all the distance sensors and the corresponding counting designated for distance measurement (time of flight measurement).

Numeral 22 designates the sensor modules, in which one or more ultrasonic sensors are summarized.

With 24 a comparator module for realizing a reduction in speed and 26 is referred to a comparator module to achieve an emergency stop of the vehicle. 2 The comparator modules 24, 26 can be programmed with appropriate thresholds prevail constantly in the Komparatormodulen and can be changed, for example, range specifications in areas between 0.3 and 10 m.

Numeral 28 designates a code switch for the manual input of threshold values ​​on the one hand via a threshold-30 in the comparator 24 for speed reduction, and the other, on a threshold module 32 in the comparator 26 to trigger a halt. To trigger an emergency stop in addition an independent emergency stop switch 34 is provided. The comparator modules 24 and 26 and the emergency switch 34 acting on an external interface 36, which is indicated by a dotted line. Starting from the comparator 26 lines 38 led to the interface 36, which ultrasonic sensor caused a sensor identification, ie a determination enable triggering.

The circuit described operates as follows:

By switching both the measurement cycle (repeat the measurement process) as well as the resolution cycle (counting the distance measurement) are triggered synchronously, so that all the sensor modules 22 are initiated simultaneously in the time module 20th The measurement and dissolution rate is variable (minimum 120 ms).

The thus initiated sensor modules 22 provide the actual ultrasonic sensors 40 (in FIG. 2 not shown) and measure the returning echo signals. Distance information is represented in counts a time of flight measurement.

The first echo signal falls below the predetermined threshold value of the distance from an obstacle triggers the comparator 24, a speed reduction or comparator 26 from an emergency stop. The speed reduction causes a slowing down of the initially high vehicle speed and a gentle approach to obstacles.

The echo signals can additionally serve as guidance signals for control of the drive and the steering of the vehicle. 2

Each ultrasonic sensor is "programmed" by its removal specification for the Gechwindigkeitsreduktion and for the emergency stop individually or globally in terms of its safety and effective range. So any safety contours may be generated.

Instead on the manually operated coding 28, the thresholds for the comparator modules 24, 26 are also defined with the help of telemetry or by radio.

Fig. 3 shows a constructive embodiment of a receiving device for a plurality, in the illustrated case two ultrasonic sensors 40. Each ultrasonic sensor 40 is held in a spherical pivot head 42 received in turn in a bore 44 of the vehicle 2 (FIG. 1) fixed to the housing 46 and is supported by a pressure plate 48 therein. The pressure plate 48 is connected via adjusting screws 50 to the housing 46 in a desired angular position to do so.