Monitoring device for a slipform paver for monitoring the compaction of concrete and method for monitoring the compaction of concrete during the operation of a slipform paver

Abstract

A monitoring system is provided for a slipform paver for monitoring the compaction of concrete placed in a slipform with at least one concrete compaction device, which has a hydraulic motor for driving a vibration-generating imbalance. In addition, a method is provided for monitoring the compaction of concrete placed in a slipform of a slipform paver with at least one concrete compaction device, which has a hydraulic motor for driving a vibration-generating imbalance. The monitoring system and the method are characterized in that the pressure in the hydraulic fluid system is measured by at least one pressure sensor arranged in the hydraulic fluid system, which pressure sensor generates a pressure signal correlating with the pressure in the hydraulic fluid, and the compaction of the concrete placed in the slipform is concluded on the basis of an analysis of the pressure signal.

1 . A slipform paver, comprising:
 a slipform configured to form a concrete structure from concrete;   at least one hydraulic concrete compaction device including a hydraulic motor for driving a vibration-generating imbalance;   a hydraulic fluid system configured to provide a hydraulic fluid to the hydraulic motor; and   a monitoring system for monitoring a compaction of the concrete, the monitoring system including:
 at least one pressure sensor arranged in the hydraulic fluid system, and configured to generate a pressure signal correlated to a pressure in the hydraulic fluid; and 
 a controller configured to receive the pressure signal and to evaluate the compaction of the concrete based on an analysis of the pressure signal. 
   
     
     
         2 . The slipform paver according to  claim 1 , wherein the controller is configured such that an amplitude spectrum of the pressure signal is determined for analyzing the pressure signal. 
     
     
         3 . The slipform paver according to  claim 2 , wherein the controller is configured such that the pressure signal is sampled, and the amplitude spectrum of the pressure signal is ascertained by a discrete-time Fourier transform (DFT). 
     
     
         4 . The slipform paver according to  claim 3 , wherein the discrete-time Fourier transform (DFT) is a discrete-time fast Fourier transform (FFT) of the pressure signal. 
     
     
         5 . The slipform paver according to  claim 2 , wherein the controller is configured such that:
 at least one spectral component, which is attributable to the imbalance, is ascertained from the amplitude spectrum of the pressure signal, and a frequency of the at least one spectral component is determined and compared with at least one predetermined limit value; and   a control signal is generated if the at least one limit value is exceeded and/or undershot.   
     
     
         6 . The slipform paver according to  claim 5 , wherein the controller is configured such that a threshold value for an amplitude of a harmonic of the pressure signal is predetermined for evaluating the pressure signal. 
     
     
         7 . The slipform paver according to  claim 5 , wherein the controller includes an output unit configured to receive the control signal and configured such that an improper compaction of the concrete during operation of the slipform paver is indicated by an acoustic and/or optical and/or a tactile signal, if the output unit receives the control signal, or that proper compaction of the concrete during operation of the slipform paver is indicated by an acoustic and/or optical and/or tactile signal if the output unit does not receive the control signal. 
     
     
         8 . The slipform paver according to  claim 1 , wherein the hydraulic fluid system comprises a pressure line leading to the hydraulic motor of the concrete compaction device and a return line leading from the hydraulic motor, and the at least one pressure sensor is arranged in or on the pressure line and/or the return line. 
     
     
         9 . The slipform paver according to  claim 1  wherein the controller is configured such that a rotational speed of the hydraulic motor of the at least one concrete compaction device is controlled based at least in part on the analysis of the pressure signal generated by the at least one pressure sensor. 
     
     
         10 . The slipform paver according to  claim 9 , wherein:
 the hydraulic fluid system includes a flow control valve for setting a volume flow of the hydraulic fluid flowing into the hydraulic motor of the at least one concrete compaction device; and   the controller is configured such that the flow control valve is actuated as a function of the pressure signal such that the concrete compaction device is operated at a predetermined rotational speed.   
     
     
         11 . A method of monitoring a compaction of concrete placed in a slipform of a slipform paver with at least one hydraulic concrete compaction device, which has a hydraulic motor for driving a vibration-generating imbalance, which is operated with a hydraulic fluid that is provided in a hydraulic fluid system, the method comprising:
 measuring a pressure in the hydraulic fluid using at least one pressure sensor arranged in the hydraulic fluid system, which pressure sensor generates a pressure signal correlating with the pressure in the hydraulic fluid; and   determining the compaction of the concrete placed into the slipform of the slipform paver based at least in part on an analysis of the pressure signal.   
     
     
         12 . The method according to  claim 11 , wherein the analysis of the pressure signal includes determining an amplitude spectrum of the pressure signal by a discrete-time Fourier transform (DFT). 
     
     
         13 . The method according to  claim 12  wherein the discrete-time Fourier transform (DFT) is a discrete-time fast Fourier transform (FFT). 
     
     
         14 . The method according to  claim 12 , wherein at least one spectral component, which is attributable to the imbalance, is ascertained from the amplitude spectrum of the pressure signal and the frequency of the at least one spectral component is determined and compared with at least one predetermined limit value, wherein a control signal is generated if the predetermined limit value is exceeded and/or undershot and an acoustic and/or optical and/or tactile signal is used to indicate improper compaction of the concrete during operation of the slipform paver if the control signal is generated, or an acoustic and/or optical and/or tactile signal is used to indicate proper compaction of the concrete during operation of the slipform paver if the control signal is not generated. 
     
     
         15 . The method according  claim 11 , wherein a rotational speed of the hydraulic motor of the at least one concrete compacting device is controlled on the basis of the analysis of the pressure signal generated by the at least one pressure sensor. 
     
     
         16 . The method according to  claim 15 , wherein a flow control valve is included in the hydraulic fluid system for setting the volume flow of the hydraulic fluid flowing into the hydraulic motor of the at least one concrete compacting device, the method further comprising:
 actuating the flow control valve as a function of the pressure signal correlating with the pressure in the hydraulic fluid such that the concrete compacting device is operated at a predetermined rotational speed.