Safety system for a vehicle and method with a safety system for a vehicle

Abstract

A safety system (1) for a vehicle (2), comprising a spatially resolving safety sensor (3) which determines distance values to objects (4) in a first monitoring area (5), wherein the safety sensor (3) has at least one protective field (6) and at least one warning field (7) in the monitoring area (5), wherein the warning field (7) has a greater extent than the protective field (6), at least in the direction of travel, a control and evaluation unit (8) which is designed to evaluate the distance values and to output control signals depending on the distance information, wherein the control and evaluation unit (8) is designed to reduce a driving speed when an object is detected in the warning field (7), and the control and evaluation unit (8) is designed to stop a driving speed when an object (4) is detected in the protective field (6), wherein at least one acceleration sensor (9) is arranged,wherein the acceleration sensor (9) detects acceleration values of the vehicle, wherein the acceleration sensor (9) is connected to the control and evaluation unit (8), wherein the control and evaluation unit (8) is designed to evaluate the acceleration values, wherein the control and evaluation unit (8) is designed to continuously evaluate the acceleration values at least from the time of object detection of an object (4) in the warning field (7) of the safety sensor (3) in order to monitor a negative acceleration or a braking process of the vehicle (2), characterized in that the control and evaluation unit (8) is designed to detect and evaluate acceleration values of the safety sensor (3) and to compare them with acceleration values of the acceleration sensor (9), or the control and evaluation unit (8) is designed to compare acceleration values of a radio positioning system and acceleration values of the acceleration sensor (9).

Description

The present invention relates to a safety system for a vehicle according to the preamble of claim 1 and a method with a safety system for a vehicle according to the preamble of claim 9.In the field of industrial safety technology, vehicles are equipped with safety sensors for personal protection.DE 10 2011 077 998 A1 discloses a method for information validation, wherein a laser scanner and an acceleration sensor are provided, wherein the information of the laser scanner and of the acceleration sensor is fused to form a common composite information item.DE 10 2013 220 526 A1 discloses a vehicle having a laser scanner or lidar scanner as environment sensor and an acceleration sensor, wherein the data are compared with one another.According to EP 3 026 459 B1, a vehicle has a laser scanner and an acceleration sensor, wherein a reference contour is adapted to acceleration-dependent movements of the vehicle.DE 10 2019 111 642 B3 discloses a safety system for protecting the environment of a vehicle, which has an optoelectronic safety sensor for monitoring the environment, a first input which can be connected to a first kinematic sensor for determining a first speed value for the speed of the vehicle, and a control and evaluation unit which is designed to detect objects in the environment on the basis of sensor data of the safety sensor and to assess whether or not the vehicle is protected taking into account the speed of the vehicle. In this case, an inertial measurement unit is provided in order to determine movement information of the vehicle, and the control and evaluation unit is furthermore designed to compare the first speed value and the movement information with one another.DE 10 2012 203 132 A1 discloses a rail vehicle brake device having at least one electrodynamic brake, which comprises a drive unit, which has at least one drive motor and a power supply unit for supplying the drive motor in a traction mode of the drive unit. In order to increase the safety of the electrodynamic brake, it is proposed that the rail vehicle brake device has at least two brake control units, wherein in a first brake mode a first brake control unit controls the power supply unit in an active state for providing a braking action, a first brake action monitoring unit and a switching unit which serves to switch over, depending on a braking action characteristic variable in the first brake mode, into a second brake mode, in which the second brake control unit controls the power supply unit in an active state for providing a braking action.It is an object of the invention to provide an improved security system.The object is achieved according to claim 1 by a safety system for a vehicle, comprising a spatially resolving safety sensor which determines distance values to objects in a first monitoring area, wherein the safety sensor has at least one protected field and at least one warning field in the monitoring area, wherein the warning field has a greater extent than the protected field at least in the direction of travel, a control and evaluation unit which is designed to evaluate the distance values and to output control signals depending on the distance information, wherein the control and evaluation unit is designed to reduce a travel speed in the case of a detected object in the warning field and the control and evaluation unit is designed to stop a travel speed in the case of a detected object, wherein at least one acceleration sensor is arranged, wherein the acceleration sensor detects acceleration values of the vehicle, wherein the acceleration sensor is connected to the control and evaluation unit, wherein the control and evaluation unit is designed to evaluate the acceleration values, wherein the control and evaluation unit is designed to continuously evaluate the acceleration values at least from the time of object detection of an object in the warning field of the safety sensor, in order to monitor a negative acceleration or a braking process of the vehicle.The object is further achieved according to claim 9 by a method with a safety system for a vehicle, comprising a spatially resolving safety sensor which determines distance values to objects in a first monitoring area, wherein the safety sensor has at least one protected field and at least one warning field in the monitoring area, wherein the warning field has a greater extent than the protected field at least in the direction of travel, a control and evaluation unit evaluates the distance values and outputs control signals depending on the distance information, wherein the control and evaluation unit reduces a travel speed in the case of a detected object in the warning field and the control and evaluation unit stops a travel speed in the case of a detected object in the protected field, wherein at least one acceleration sensor is arranged, wherein the acceleration sensor detects acceleration values of the vehicle, wherein the acceleration sensor is connected to the control and evaluation unit, wherein the control and evaluation unit evaluates the acceleration values, wherein the control and evaluation unit continuously evaluates the acceleration values at least from the time of object detection of an object in the warning field of the safety sensor in order to monitor a negative acceleration or a braking process of the vehicle.According to the invention, the reduction of the vehicle speed, i.e. a negative acceleration, or a braking process is monitored in a simple and cost-effective manner, so that this function is executed as a safety function, i.e. according to functional safety standards.The safety sensor has, for example, safety-directed outputs. For example, these are semiconductor switching outputs (output safety switching devices, OSSDs for short) or safety data interfaces such as IO-link safety, CIP safety or the like, which are used for a primary safety function, for example to actuate a brake of the vehicle.Safety systems or safety sensors used in safety technology must operate particularly reliably and intrinsically safe and must therefore meet high safety requirements, for example the standard EN13849 for machine safety and the device standard EN61496 for contactless protective devices (BWS).The term "functionally safe" is to be understood in the sense of the stated or comparable standards, i.e. measures are taken to cope with errors up to a specified safety level. The safety system or the safety sensor can therefore be designed to be intrinsically safe. The safety system and / or at least the safety sensor also generate non-safe data, such as raw data, point clouds or the like. The opposite term is not reliable, too reliable for non-reliable devices, transmission paths, evaluations and the like and the requirements for error safety stated are accordingly not fulfilled in this case.To reduce the speed of the vehicle, the warning fields are used as triggers. For this purpose, for example, a single-channel signal is used, which is fed to the control and evaluation unit. This signal is not carried out reliably, for example, and thus an automation function without a safety requirement.The acceleration sensor is used to measure the change in speed when the speed reduction is actuated, for example by mathematically integrating the acceleration signal with the start of the warning field injury.The estimation of the velocity change can be carried out, for example, either with a simple mathematical integration or with a state estimator such as a suitable Kalman filter. In such a Kalman filter, the state memories are emptied at the start of the measurement-i.e. with the edge of the report signal-in a manner analogous to the zeroing of the memory of an integrator.According to the invention, a simple method for safely reducing the speed is provided.A diagnosis comprises the entire system of the vehicle and of the safety system, i.e. both the electrical and the mechanical part and thus achieves a high level of diagnostic coverage.No electrical test pulses or two-channel or other safety measures are necessary for the signal which signals the mode with reduced speed of the control. A simple digital signal is sufficient.Also, expensive rotary encoders are not necessary.For example, the safety sensor is an optoelectronic sensor, wherein a transmitter is a light transmitter and a receiver is a light receiver for contactless scanning of the monitoring area, by transmitting light beams into the monitoring area and detecting returning reflected light beams from objects within the monitoring area and evaluating the returning reflected light beams by the control and evaluation unit.For example, the optoelectronic sensor is a time-of-flight sensor, for example a laser scanner or a time-of-flight camera. For example, the optoelectronic sensor is a safety laser scanner, a safety camera or any optoelectronic environment detection sensor system. The laser scanner has, for example, a light deflection unit, as a result of which the emitted light beam cyclically scans the environment.For example, the optoelectronic sensor is configured for detecting objects in a three-dimensional monitoring region, having at least one image sensor which can record a pixel image of the monitoring region by means of a plurality of light receiving elements, and having at least the control and evaluation unit which is configured for detecting an object from image data of the pixel image, wherein a plurality of image sensors is provided which each have at least one pixel row having light receiving elements and wherein the image sensors are arranged at a distance from one another, such that each image sensor can record its own plane of the monitoring region, wherein the image sensors are arranged such that the planes are mutually overlapping and substantially parallel to one another or diverge from one another in a fan shape proceeding from the image sensors. The protected field is a protected area or protected volume and the warning field is a warning area or warning volume.For example, the optoelectronic sensor is a laser scanner having at least one transmitting element and at least one receiving element and the control and evaluation unit for evaluating the time of flight of light beams from the transmitting element via an object to the receiving element, wherein a plurality of transmitting elements and a plurality of receiving elements are arranged in a circular segment shape in a common housing, wherein the light beams are emitted and / or received in fan shape in different angular directions.For example, the safety sensor is a radar sensor, wherein a transmitter is a radar transmitter, wherein a receiver is a radar receiver for contactless scanning of the monitoring area, by transmitting radio waves into the monitoring area and detecting returning reflected radio waves from objects within the monitoring area and evaluating the returning reflected radio waves by the control and evaluation unit.The radar sensor or a radar device has the radar transmitter and the radar receiver in order to emit a radar signal into the monitored zone and to receive it again from there. Radar transmitters and radar receivers are preferably jointly designed as transceivers. A control and evaluation unit evaluates the received signal of the radar receiver in order to determine object properties. Preferably, a distance from the signal transit time of the radar signal is measured. Other exemplary object characteristics are speed or merely determining the presence or absence of objects in the first monitoring area.Radar monitoring is known and is used in many fields of application. Various principles are known for measuring the distance to a detected object, for example pulse radar, continuous wave radar or FMCW radar (frequency-modulated continuous wave). Direct measurement of a velocity utilizing the Doppler effect is also a typical radar application.Radar penetrates many materials and is therefore relatively robust. This also applies to weather influences, such as fog, rain or snow in the exterior. A radar system can also detect the speed by means of the Doppler effect in addition to the position.The vehicle may be, for example, a leadless vehicle, a leadless vehicle, an autonomous guided vehicle (AGC), an automated mobile robot (AMR), or an industrial mobile robot (IMR). The vehicle thus has a drive and can be moved in various directions.In a further development of the invention, the control and evaluation unit is designed to check a limit value for the negative acceleration, and if the limit value for the negative acceleration is not reached, a control signal for stopping the vehicle is output by the control and evaluation unit.Only if a sufficient speed change is reached after a defined deceleration time does the vehicle continue to drive at a reduced speed. If not, a hard brake curtain is initiated.A prerequisite is that it is ensured, for example due to the design, that the vehicle does not exceed a defined maximum speed, which can be regarded as being the case in almost all cases, since the calculation of the protected fields is also based on the maximum speed.In a further development of the invention, the safety sensor, the control and evaluation unit and the acceleration sensor are arranged in a housing.The acceleration sensor is thus completely integrated in the safety sensor. This allows simple integration of the safety sensor with the control and evaluation unit into the safety system. A vehicle controller thus does not need to monitor the speed reduction and also does not need the acceleration sensor.In a development of the invention, the acceleration sensor is a multiaxial acceleration sensor. The acceleration sensor is designed, for example, to evaluate three different spatial directions. Furthermore, the acceleration sensor is designed, for example, to evaluate three different solid angles.If the vehicle is travelling in only one direction, the acceleration in the direction of travel is measured in a defined manner. If it is not possible to determine the orientation of the acceleration sensor, e.g. because the vehicle can travel forwards and backwards, then with a multiaxial acceleration sensor the amount of acceleration can be calculated from the components. In the case of two axles: In the case of three axles: the control and evaluation unit can hereby not distinguish whether a braking process or a speed increase is involved. However, the amount of speed or acceleration is sufficient for diagnostic purposes, since an erroneous speed increase, which then also delivers the correct amount of the measured variable, can be ruled out.According to the invention, the control and evaluation unit is designed to record and evaluate acceleration values of the safety sensor on the basis of the sensor values of the safety sensor and to compare them with acceleration values of the acceleration sensor.The variance in sensor location function may be increased by fusing the primary location data of the safety sensor to the accelerometer. However, a basic problem here is that the alignment of the sensor axes is not known in the general case. However, if a multiaxial acceleration sensor is used, then the amount of acceleration may be used to improve the quality of position and motion estimation. In the two-dimensional case, the amount isIn the first step, the state variables position p̂, speed v̂ and acceleration δ are estimated using a suitable state estimator, e.g. a Kalman filter, on the basis of the primary sensor localization function. In the second step, the correction takes place. Here, the estimated value of the acceleration ß is corrected. The direction from the first estimate is maintained and the magnitude is scaled by the factor from the measurement with the accelerometer.The corrected value is obtained from ß c= ( ß / | | | ß | | | )· | a accel||.This state variable significantly improves the quality of a position system, in particular in the case of faults such as in poor localization, i.e. if reference marks are missing at the scanner, for example.According to the invention, the control and evaluation unit is designed to record acceleration values of a radio location system on the basis of the position values of a radio transponder and to compare acceleration values of the acceleration sensor with one another. The radio transponder is arranged on the vehicle.The measurement deviation of the sensor localization function can be increased by fusing the primary localization data of a radio transponder of a radio localization system with the acceleration sensor. However, a basic problem here is that the alignment of the sensor axes is not known in the general case. However, if a multiaxial acceleration sensor is used, then the amount of acceleration may be used to improve the quality of position and motion estimation. In the two-dimensional case, the amount isIn the first step, the state variables position p̂, speed v̂ and acceleration δ are estimated using a suitable state estimator, e.g. a Kalman filter, on the basis of the primary sensor localization function. In the second step, the correction takes place. Here, the estimated value of the acceleration ß is corrected. The direction from the first estimate is maintained and the magnitude is scaled by the factor from the measurement with the accelerometer.The corrected value is obtained from ß c= ( ß / | | | ß | | | )· | a accel||.This state variable significantly improves the quality of a position system, in particular in the case of disturbances such as in poor localization, i.e. if, for example, radio stations in the radio localization system are covered.The locating of the radio transponders is effected by time-of-flight measurements of radio signals which are exchanged cyclically between the radio transponders and, for example, a plurality of fixed radio stations. This evaluation works very well if the signals are transmitted with sufficient signal strength and on straight or direct propagation paths.The signals of a radio transponder are received by, for example, a plurality of fixed radio stations or anchor stations and the basis for the locating is created by a time-of-flight measurement, for example, "Time of arrival" (TOA) or, for example, "Time Difference of Arrival" (TDOA). The position of a radio transponder is then calculated or estimated on a control and evaluation unit, for example a central RTLS server (real-time location system server), which is connected to all radio stations or anchor stations via a wireless or wired data connection. This mode of locating is called RTLS mode (real-time location system mode).In particular, the radio location system has at least three arranged radio stations, wherein the position data can be transmitted from the radio station of the radio location system to the control and evaluation unit.In particular, the radio location system is an ultra-wideband radio location system, wherein the frequency used is in the range of 3.1 GHz to 10.6 GHz.An absolute bandwidth in an ultra-wideband radio location system is at least 500 MHz or a relative bandwidth is at least 20% of the central frequency.The range of such a radio location system is, for example, 0 to 50 m. In this case, the short time duration of the radio pulses is used for the location. The radio location system thus only transmits radio waves with a low energy.In a further development of the invention, the control and evaluation unit is configured in two channels. The safety sensor, which is configured in two channels according to safety category 3 or 4, has the acceleration sensor.To meet the above-mentioned safety standards, a number of measures must be taken, such as, for example, safe electronic evaluation by redundant and / or diversity electronics or various function monitoring systems, especially the monitoring of the contamination of optical components including a front screen.In a further development of the invention, the control and evaluation unit is configured in a single channel with a test channel. The safety sensor, which is configured in one channel with test channel according to safety category 2, has the acceleration sensor.In a further development of the invention, the control and evaluation unit is designed to automatically learn a negative acceleration of the vehicle. Automatic setting can be effected as follows: In a measurement / setting mode, the deceleration time and the change in speed are taught by the safety sensor or by the control and evaluation unit during a controlled setting process. The trigger for this is again the warning field signal. The safety sensor measures the speed change and the deceleration time automatically. These values are to be manually confirmed by the user--the tolerance ranges (time and speed) are optionally still manually adjusted.In a further development of the invention, the control and evaluation unit has means for inputting a negative acceleration of the vehicle. An expectation window, i.e. a time and speed change window, is directly configured by the user. For this purpose, a configuration interface is provided, for example, on a configuration computer which is connected to the safety sensor.The invention is also explained below with regard to further advantages and features with reference to the attached drawing on the basis of exemplary embodiments. The figures of the drawing show in: FIGS. 1 and 2 each show a safety system; FIG. 3 shows signal diagrams of FIG. 1 ; FIG. 4 shows a signal diagram for changing speed;In the following figures, identical parts are provided with identical reference numerals.FIG. 1 shows a safety system 1 for a vehicle 2, comprising a spatially resolving safety sensor 3 which determines distance values to objects 4 in a first monitoring region 5, wherein the safety sensor 3 has at least one protected field 6 and at least one warning field 7 in the monitoring region 5, wherein the warning field 7 has a greater extent than the protected field 6 at least in the direction of travel, a control and evaluation unit 8 which is designed to evaluate the distance values and to output control signals depending on the distance information, wherein the control and evaluation unit 8 is designed to reduce a travel speed in the case of a detected object 4 in the warning field 7 and the control and evaluation unit 8 is designed to stop a travel speed in the case of a detected object 4, wherein at least one acceleration sensor 9 is arranged, wherein the acceleration sensor 9 detects acceleration values of the vehicle 2, wherein the acceleration sensor 9 is connected to the control and evaluation unit 8, wherein the control and evaluation unit 8 is designed to evaluate the acceleration values, wherein the control and evaluation unit 8 is designed to continuously evaluate the acceleration values at least from the time of object detection of an object 4 in the warning field 7 of the safety sensor 3 in order to monitor a negative acceleration or a braking process of the vehicle 2.The safety sensor 3 has, for example, safety-directed outputs. For example, these are semiconductor switching outputs (output safety switching devices, OSSDs for short) or safety data interfaces such as IO-link safety, CIP safety or the like, which are used for a primary safety function, for example to actuate a brake of the vehicle 2 for standstill of a vehicle 2.To reduce the speed of the vehicle 2, the warning field 7 is used as a trigger. For this purpose, for example, a single-channel signal is used, which is fed to the control and evaluation unit 8. This signal is not carried out reliably, for example, and thus an automation function without a safety requirement.This acceleration sensor 9 is used to measure the change in speed when the speed reduction is actuated, for example by integrating the acceleration signal with the start of the warning field injury.The estimation of the velocity change can be carried out, for example, either with a simple integration or with a state estimator such as a suitable Kalman filter. In such a Kalman filter, the state memories are emptied at the start of the measurement-i.e. with the edge of the report signal-in a manner analogous to the zeroing of the memory of an integrator.For example, the safety sensor 3 is an optoelectronic sensor, wherein a transmitter is a light transmitter and a receiver is a light receiver for touch-free scanning of the monitoring region 5, by transmitting light beams into the monitoring region 5 and detecting returning reflected light beams from objects 4 within the monitoring region and evaluating the returning reflected light beams by the control and evaluation unit 8.For example, the optoelectronic sensor is a time-of-flight sensor, for example a laser scanner or a time-of-flight camera.For example, the optoelectronic sensor is a laser scanner having at least one transmitting element and at least one receiving element and the control and evaluation unit 8 for evaluating the time of flight of light beams from the transmitting element via an object to the receiving element, wherein a plurality of transmitting elements and a plurality of receiving elements are arranged in a circular segment shape in a common housing 10, wherein the light beams are emitted and / or received in fan-shaped fashion in different angular directions.For example, the safety sensor 3 is a radar sensor, wherein a transmitter is a radar transmitter, wherein a receiver is a radar receiver for contactless scanning of the monitored area, by transmitting radio waves into the monitored area and detecting returning reflected radio waves from objects within the monitored area 5 and evaluating the returning reflected radio waves by the control and evaluation unit 8.The radar sensor or a radar device has the radar transmitter and the radar receiver in order to emit a radar signal into the monitoring region 5 and to receive it again from there. Radar transmitters and radar receivers are preferably jointly designed as transceivers. The control and evaluation unit 8 evaluates the received signal of the radar receiver in order to determine object properties. Preferably, a distance from the signal transit time of the radar signal is measured.The control and evaluation unit 8 is preferably designed to check a limit value for the negative acceleration, and if the limit value for the negative acceleration is not reached, a control signal for stopping the vehicle 2 is output by the control and evaluation unit 8.Only if a sufficient speed change is reached after a defined deceleration time does the vehicle 2 continue to drive at a reduced speed. If not, a hard brake curtain is initiated.According to FIG. 2, the safety sensor 3, the control and evaluation unit 8 and the acceleration sensor 9 are arranged in a housing 10.For example, the acceleration sensor 9 is a multiaxial acceleration sensor. The acceleration sensor 9 is designed, for example, to evaluate the three spatial directions. Furthermore, the acceleration sensor 9 is designed, for example, to evaluate the three solid angles.For example, the control and evaluation unit 8 is designed to record and evaluate acceleration values of the safety sensor 3 on the basis of the sensor values of the safety sensor 3 and to compare them with acceleration values of the acceleration sensor 9.FIG. 3 shows signal diagrams of FIG. 1. t 0 is the time at which the object 4 is detected by the warning field and is detected by the control and evaluation unit 8. The first signal is the driving speed shown, which is reduced or slowed down after the object is detected. The second signal indicates the acceleration and the negative acceleration from the time t 0. The third signal is the estimated speed difference. The change in speed is determined from the measured acceleration of the acceleration sensor 9. The fourth signal is the report signal to the vehicle controller, wherein a speed reduction is forwarded to the vehicle controller from the time t 0 onward.The measurement deviation of the sensor localization function can be increased by fusing the primary localization data of the safety sensor 3 with the acceleration sensor 9.In the first step, the state variables position p̂, speed v̂ and acceleration δ are estimated using a suitable state estimator, e.g. a Kalman filter, on the basis of the primary sensor localization function. In the second step, the correction takes place. Here, the estimated value of the acceleration ß is corrected. The direction from the first estimate is retained and the amount is scaled by the factor from the measurement with the acceleration sensor 9.For example, the control and evaluation unit 8 is designed to record acceleration values of a radio location system on the basis of the position values of a radio transponder and to compare acceleration values of the acceleration sensor 9 with one another.The measurement deviation of the sensor localization function can be increased by fusing the primary localization data of a radio transponder of a radio localization system to the acceleration sensor 9.In the first step, the state variables position p̂, speed v̂ and acceleration δ are estimated using a suitable state estimator, e.g. a Kalman filter, on the basis of the primary sensor localization function. In the second step, the correction takes place. Here, the estimated value of the acceleration ß is corrected. The direction from the first estimate is retained and the amount is scaled by the factor from the measurement with the acceleration sensor 9.The locating of the radio transponders is effected by time-of-flight measurements of radio signals which are exchanged cyclically between the radio transponders and, for example, a plurality of fixed radio stations.In particular, the radio location system has at least three arranged radio stations, wherein the position data can be transmitted from the radio station of the radio location system to the control and evaluation unit.In particular, the radio location system is an ultra-wideband radio location system, wherein the frequency used is in the range of 3.1 GHz to 10.6 GHz. The transmission energy per radio station is, for example, at most 0.5 mW. For example, the transmission energy per radio station can also be values greater than 0.5 mW. For example, 1 mW or more.For example, the control and evaluation unit 8 is configured in two channels.For example, the control and evaluation unit 8 is configured in a single channel with a test channel.For example, the control and evaluation unit 8 is designed to automatically learn a negative acceleration of the vehicle 2.Automatic setting can be effected as follows: in a measurement / setting mode, the deceleration time and the change in speed are taught by the safety sensor 3 or by the control and evaluation unit 8 during a controlled setting process. The trigger for this is again the warning field signal. The safety sensor 3 measures the speed change and the deceleration time automatically. These values can be manually confirmed by the user according to FIG. 4--the tolerance ranges (time and with regard to speed) are optionally still manually adjusted.For example, the control and evaluation unit 8 has means for inputting a negative acceleration of the vehicle 2. An expectation window, i.e. a time and speed change window, is directly configured by the user. For this purpose, a configuration interface is provided, for example, on a configuration computer which is connected to the safety sensor 3.Reference Number:1 Safety system 2 Vehicle 3 Safety sensor 4 Object 5 Monitoring region 6 Protected field 7 Warning field 8 Control and evaluation unit 9 Acceleration sensor 10 Housing

Claims

Safety system (1) for a vehicle (2), comprising a spatially resolving safety sensor (3) which determines distance values to objects (4) in a first monitoring region (5), wherein the safety sensor (3) has at least one protected field (6) and at least one warning field (7) in the monitoring region (5), wherein the warning field (7) has a greater extent than the protected field (6) at least in the direction of travel, a control and evaluation unit (8) which is designed to evaluate the distance values and to output control signals depending on the distance information, wherein the control and evaluation unit (8) is designed to reduce a travel speed in the case of a detected object in the warning field (7) and the control and evaluation unit (8) is designed to stop a travel speed in the case of a detected object (4), wherein at least one acceleration sensor (9) is arranged, wherein the acceleration sensor (9) detects acceleration values of the vehicle, wherein the acceleration sensor (9) is connected to the control and evaluation unit (8), wherein the control and evaluation unit (8) is designed to evaluate the acceleration values, wherein the control and evaluation unit (8) is designed to continuously evaluate the acceleration values at least from the time of object detection of an object (4) in the warning field (7) of the safety sensor (3) in order to monitor a negative acceleration or a braking process of the vehicle (2), characterized in that the control and evaluation unit (8) is designed to detect and evaluate acceleration values of the safety sensor (3) and to compare them with acceleration values of the acceleration sensor (9) or the control and evaluation unit (8) is designed to compare acceleration values of a radio location system and acceleration values of the acceleration sensor (9) with one another.Safety system (1) according to Claim 1, characterized in that the control and evaluation unit (8) is designed to check a limit value for the negative acceleration, and if the limit value for the negative acceleration is not reached, a control signal for stopping the vehicle (2) is output by the control and evaluation unit (8).Safety system (1) according to one of the preceding claims, characterized in that the safety sensor (3), the control and evaluation unit (8) and the acceleration sensor (9) are arranged in a housing (10).Safety system (1) according to one of the preceding claims, characterized in that the acceleration sensor (9) is a multiaxial acceleration sensor (9).Safety system (1) according to one of the preceding claims, characterized in that the control and evaluation unit (8) is of two-channel design.Safety system (1) according to one of the preceding claims, characterized in that the control and evaluation unit (8) is configured in a single channel with a test channel.Safety system (1) according to one of the preceding claims, characterized in that the control and evaluation unit (8) is designed to automatically learn a negative acceleration of the vehicle (2).Safety system (1) according to one of the preceding claims, characterized in that the control and evaluation unit (8) has means for inputting (11) a negative acceleration of the vehicle (2).Method with a safety system (1) for a vehicle (2), comprising a spatially resolving safety sensor (3) which determines distance values to objects in a first monitoring area, wherein the safety sensor (3) has at least one protected field (6) and at least one warning field (7) in the monitoring area (5), wherein the warning field (7) has a greater extent than the protected field (6) at least in the direction of travel, a control and evaluation unit (8) evaluates the distance values and outputs control signals depending on the distance information, wherein the control and evaluation unit (8) reduces a travel speed in the case of a detected object (4) in the warning field (7) and the control and evaluation unit (8) stops a travel speed in the case of a detected object (4), wherein at least one acceleration sensor (9) is arranged, wherein the acceleration sensor (9) detects acceleration values of the vehicle (2), wherein the acceleration sensor (9) is connected to the control and evaluation unit (8), wherein the control and evaluation unit (8) evaluates the acceleration values, wherein the control and evaluation unit (8) continuously evaluates the acceleration values at least from the time of object detection of an object (4) in the warning field (7) of the safety sensor (3) in order to monitor a negative acceleration or a braking process of the vehicle (2), characterized in that the control and evaluation unit (8) is designed to detect and evaluate acceleration values of the safety sensor (3) and to compare them with acceleration values of the acceleration sensor (9) or the control and evaluation unit (8) is designed to compare acceleration values of a radio location system and acceleration values of the acceleration sensor (9) with one another.

Images